906 research outputs found

    A Feasible Approach for an Early Manned Lunar Landing. Part I: Summary Report of Ad Hoc Task Group Study

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    This report, in two parts, presents a program development plan for attempting a first manned lunar landing in 1967. The two parts consist of a Summary Report and a Detailed Report representing the coordinated output of the ad hoc task group assigned to the study. The study was started in response to the request for such a study by the Associate Administrator in his memorandum of May 2, 1961 establishing the Ad Hoc Task Group. The purpose of the study was to take a first cut at the tasks associated with the design, development and construction of the equipment and facilities as well as the development of the crews, and to show the time phasing of these tasks. Included are the space science, life science and advanced technology tasks whose data and results are needed for designing and developing the systems required in carrying out the mission

    Effects of Altitude on Turbojet Engine Performance

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    Component and over-all performance characteristics of several turbojet engines investigated in the altitude facilities of the NACA Lewis Laboratory during the last several years are summarized to indicate the effects of altitude on turbojet engine performance. Data presented show that failure of turbojet engine performance to generalize for all altitudes can be traced to reductions in compressor efficiency, corrected air flow, and combustion efficiency at altitude. In addition, it is shown that although engines of different design may have equal thrusts at sea level, the thrusts at altitude may vary widely because of differences in compressor performance characteristics from one engine to another

    Assessing risks of invasion through gamete performance: farm Atlantic salmon sperm and eggs show equivalence in function, fertility, compatibility and competitiveness to wild Atlantic salmon

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    Adaptations at the gamete level (a) evolve quickly, (b) appear sensitive to inbreeding and outbreeding and (c) have important influences on potential to reproduce. We apply this understanding to problems posed by escaped farm salmon and measure their potential to reproduce in the wild. Farm Atlantic salmon (Salmo salar) are a threat to biodiversity, because they escape in large numbers and can introgress, dilute or disrupt locally adapted wild gene pools. Experiments at the whole fish level have found farm reproductive potential to be significant, but inferior compared to wild adults, especially for males. Here, we assess reproductive performance at the gamete level through detailed in vitro comparisons of the form, function, fertility, compatibility and competitiveness of farm versus wild Atlantic salmon sperm and eggs, in conditions mimicking the natural gametic microenvironment, using fish raised under similar environmental conditions. Despite selective domestication and reduced genetic diversity, we find functional equivalence in all farm fish gamete traits compared with their wild ancestral strain. Our results identify a clear threat of farm salmon reproduction with wild fish and therefore encourage further consideration of using triploid farm strains with optimized traits for aquaculture and fish welfare, as triploid fish remain reproductively sterile following escape

    Altitude-wind-tunnel investigation of tail-pipe burning with a Westinghouse X24C-4B axial-flow turbojet engine

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    Thrust augmentation of an axial-flow type turbojet engine by burning fuel in the tail pipe has been investigated in the NACA Cleveland altitude wind tunnel. The performance was determined over a range of simulated flight conditions and tail-pipe fuel flows. The engine tail pipe was modified for the investigation to reduce the gas velocity at the inlet of the tail-pipe combustion chamber and to provide an adequate seat for the flame; four such modifications were investigated. The highest net-thrust increase obtained in the investigation was 86 percent with a net thrust specific fuel consumption of 2.91 and a total fuel-air ratio of 0.0523. The highest combustion efficiencies obtained with the four configurations ranged from 0.71 to 0.96. With three of the tail-pipe burners, for which no external cooling was provided, the exhaust nozzle and the rear part of the burner section were bright red during operation at high tail-pipe fuel-air ratios. With the tail-pipe burner for which fuel and water cooling were provided, the outer shell of the tail-pipe burner showed no evidence of elevated temperatures at any operating condition

    The effect of mycobacterial adjuvants on immunoglobulin production in the guinea-pig

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    The effect of mycobacterial adjuvants on antibody production against soluble protein antigens has frequently been investigated. Such investigations have, however, been limited to the effect of such adjuvants on the production of 7Sy1 and 7S y2 immunoglobulin antibodies of the guinea-pig, and the development of delayed-type hypersensitivity to the injected antigen. In this thesis, the effect of mycobacterial adjuvants on the production of antibody in all immunoglobulin classes, 7Sy1, 7Sy2 and 19S, of the guines-pig has been explored. The antigen used throughout the study was bacteriophage 0X174, which is known to stimulate the production of both 19S and 7S immuno-globulin antibodies in the guinea-pig. Levels of bacteriophage neutralising antibody in the serum of animals immunised with and without the use of adjuvants were measured using the bacteriophage neutralisation test on the eighth and twenty-first days after immunisation. The different immunoglobulins were separated from immune sera by chromatography on Sephadex G-200 or DEAE-cellulose, identified by immunoelectrophoresis, and their antibody content measured. It was found that whereas mycobacterial adjuvants cause a marked increase in the production of 7S antibody, particularly of the 78?2 immunoglobulin type, no such increase occurred in the production of 19S immunoglobulin antibody. In an attempt to explain the lack of effect of mycobacterial adjuvants on the production of 19S antibody, synthesis of bacteriophage neutralising antibody by different lymphoid tissues from immunised guinea-pigs was studied in vitro at times when the predominant circulating antibody was of the 19S or 7S immunoglobulin type. These investigations produced the surprising result that, on a unit weight basis, red bone marrow was much more active in the synthesis of 19S antibody than any other lymphoid tissue studied. In contrast, lymph node tissue, particularly from lymph nodes close to the site of antigen injection, was more active in the synthesis of 7S antibody than either spleen or bone marrow. The significance of these findings is discussed with reference to previously published work, the mode of action of mycobacterial adjuvants and the relationship between the production of 19S and TS immunoglobulin antibodies
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