Radiation hardening of components and systems for nuclear rocket vehicle applications

The results of the analysis of the S-2 and S-4B components, although incomplete, indicate that many Saturn 5 components and subsystems, e.g., pumps, valves, etc., can be radiation hardened to meet NRV requirements by material substitution and minor design modifications. Results of these analyses include (1) recommended radiation tolerance limits for over 100 material applications; (2) design data which describes the components of each system; (3) presentation of radiation hardening examples of systems; and (4) designing radiation effects tests to supply data for selecting materials

Kinetics Of Egg Production And Egg Excretion By Schistosoma Mansoni And S. Japonicum In Mice Infected With A Single Pair Of Worms

Individual male and female schistosomes approximately three weeks of age were implanted into the portal venous system of C57Bl/6 mice to produce infections with a single pair of Schistosoma mansoni or S. japonicum. Mice were killed between seven and 53 weeks after infection. Worm fecundity was measured by counting eggs accumulating in the tissues and eggs passed in the feces. Schistosoma mansoni worm pairs laid approximately 350 eggs per day with no change in the apparent rate of egg laying between eight and 52 weeks after infection and approximately one-third of the eggs were passed in the feces. Schistosoma japonicum worm pairs laid approximately 2,200 eggs per day initially and this decreased to 1,000 eggs per day by the end of the experiment, with one-third to one-half of the eggs being passed in the feces. Then was marked variability in the fecundity of individual worm pairs, but the number of eggs passed in the feces of individual mice correlated well with the number of eggs in the intestines at all time points in S. mansoni-infected mice and at the seventh and tenth week of S. japonicum infection

A Fast and Accurate Nonlinear Spectral Method for Image Recognition and Registration

This article addresses the problem of two- and higher dimensional pattern matching, i.e. the identification of instances of a template within a larger signal space, which is a form of registration. Unlike traditional correlation, we aim at obtaining more selective matchings by considering more strict comparisons of gray-level intensity. In order to achieve fast matching, a nonlinear thresholded version of the fast Fourier transform is applied to a gray-level decomposition of the original 2D image. The potential of the method is substantiated with respect to real data involving the selective identification of neuronal cell bodies in gray-level images.Comment: 4 pages, 3 figure

A preliminary design study of a microparticle accelerator final report, 30 jan. - 13 apr. 1964

Design study for 2MV microparticle accelerato

An Energy Feedback System for the MIT/Bates Linear Accelerator

We report the development and implementation of an energy feedback system for the MIT/Bates Linear Accelerator Center. General requirements of the system are described, as are the specific requirements, features, and components of the system unique to its implementation at the Bates Laboratory. We demonstrate that with the system in operation, energy fluctuations correlated with the 60 Hz line voltage and with drifts of thermal origin are reduced by an order of magnitude

Welding-base metal investigation Final report, 27 Jun. 1964 - 28 Jul. 1965

Weld defects associated with aluminum alloys - monitoring weld shielding gas purit

Persistence Of Eggs And Hepatic-Fibrosis After Treatment Of Schistosoma Mansoni-Infected Mice

In 1971 we estimated that Schistosoma mansoni eggs in the tissues of mice were destroyed with an approximate half-life of four weeks. Our present results of five experiments suggest that egg destruction is not as rapid, and no significant destruction of eggs was detected for up to 26 weeks after treatment. However, in these experiments, a mean of 60% of the eggs in intestinal tissues were found in the feces at the time of treatment. In previously reported experiments, only 15% of gut eggs were passed in the feces. We now believe that underestimation of the number of eggs passed in the feces led to an overestimation of the number of eggs destroyed in the tissues. We analyzed liver eggs separately because eggs lost from this site are unaffected by eggs passed in the feces. No significant decrease in liver eggs occurred in the present experiments, but reanalysis of previously published data showed significant egg destruction in the liver in several experiments, although at a much slower rate than previously estimated. However, inspection of the data in the previously published and present experiments does not show a convincing difference in the number of eggs in the liver after treatment. The persistence of egg shells is probably not important in the pathogenesis of disease, but is of concern in calculating worm fecundity. Hepatic collagen levels increased markedly two weeks after treatment and subsequently decreased significantly in some, but not all, experiments

Natural History Of Schistosoma Mansoni Infection In Mice: Egg Production, Egg Passage In The Feces, And Contribution Of Host And Parasite Death To Changes In Worm Numbers

Mice, C57B1/6N (B6) and BALB/cAnN (BALB), infected with Schistosoma mansoni were examined 8-26 weeks postinfection (PI) to estimate the fecundity of the worms and the contribution of death of worms and the death of heavily infected mice to the decrease in worm numbers in chronic infections. Portal worms were recovered by perfusion and the lungs were examined for parasites shunted from the portal circulation. Animals that died were more heavily infected than those that survived. Between eight and 12 weeks PI, this loss of worms resulted in a net decrease of approximately 19% of worm Fairs in surviving BALB mice, but of only 4% in B6 mice. Loss of portal worms to the lungs after the eighth week of infection was 9-13% of portal worms in BALB mice and 3-4% in B6 mice. The estimated rates of egg production by S. mansoni decreased slightly with time in both strains of mice. At 12 and 20 weeks PI, tissue eggs per worm pair and eggs passed in the feces per worm pair often decreased as the intensity of infection increased. We do not consider the loss of worms in the murine host relevant to most infections in humans because of the high intensity of infection relative to body size in mice and the high frequency of severe portal obstruction in murine infections