26 research outputs found
Investigations of Air-cooled Turbine Rotors for Turbojet Engines II : Mechanical Design, Stress Analysis, and Burst Test of Modified J33 Split-disk Rotor / Richard H. Kemp and Merland L. Moseson
A full-scale J33 air-cooled split turbine rotor was designed and spin-pit tested to destruction. Stress analysis and spin-pit results indicated that the rotor in a J33 turbojet engine, however, showed that the rear disk of the rotor operated at temperatures substantially higher than the forward disk. An extension of the stress analysis to include the temperature difference between the two disks indicated that engine modifications are required to permit operation of the two disks at more nearly the same temperature level
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NACA Research Memorandums
A full-scale J33 air-cooled split turbine rotor was designed and spin-pit tested to destruction. Stress analysis and spin-pit results indicated that the rotor in a J33 turbojet engine, however, showed that the rear disk of the rotor operated at temperatures substantially higher than the forward disk. An extension of the stress analysis to include the temperature difference between the two disks indicated that engine modifications are required to permit operation of the two disks at more nearly the same temperature level
Recommended from our members
NACA Research Memorandums
Report presenting a series of turbine wheel designs made for a turbojet engine with an axial-flow compressor. The designs were made to determine the influence of air-cooling on overall engine design, weight, critical-material content, and complexity and to assist with construction of research model full-scale turbines
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Impact of interventions and the incidence of ebola virus disease in Liberia-implications for future epidemics
To better understand the impact of national and global efforts to contain the Ebola virus disease epidemic of 2014–15 in Liberia, we provide a detailed timeline of the major interventions and relate them to the epidemic curve.
 In addition to personal experience in the response, we systematically reviewed situation reports from the Liberian government, UN, CDC, WHO, UNICEF, IFRC, USAID, and local and international news reports to create the timeline. We extracted data on the timing and nature of activities and compared them to the timeline of the epidemic curve using the reproduction number—the estimate of the average number of new cases caused by a single case.
 Interventions were organized around five major strategies, with the majority of resources directed to the creation of treatment beds. We conclude that no single intervention stopped the epidemic; rather, the interventions likely had reinforcing effects, and some were less likely than others to have made a major impact. We find that the epidemic’s turning coincided with a reorganization of the response in August–September 2014, the emergence of community leadership in control efforts, and changing beliefs and practices in the population. Ebola Treatment Units were important for Ebola treatment, but the vast majority of these treatment centre beds became available after the epidemic curve began declining. Similarly, the United Nations Mission for Ebola Emergency Response was launched after the epidemic curve had already turned.
 These findings have significant policy implications for future epidemics and suggest that much of the decline in the epidemic curve was driven by critical behaviour changes within local communities, rather than by international efforts that came after the epidemic had turned. Future global interventions in epidemic response should focus on building community capabilities, strengthening local ownership, and dramatically reducing delays in the response