7 research outputs found
Can A "Hyperspace" Really Exist?
The idea of "hyperspace" is suggested as a possible approach to faster-than-light (FTL) motion. A brief summary of a 1986 study on the Euclidean representation of space-time by the author is presented. Some new calculations on the relativistic momentum and energy of a free particle in Euclidean "hyperspace" are now added and discussed. The superimposed Energy-Momentum curves for subluminal particles, tachyons, and particles in Euclidean "hyperspace" are presented. It is shown that in Euclidean "hyperspace", instead of a relativistic time dilation there is a time "compression" effect. Some fundamental questions are presented
Advanced Stirling Radioisotope Generator Life Certification Plan
An Advanced Stirling Radioisotope Generator (ASRG) power supply is being developed by the Department of Energy (DOE) in partnership with NASA for potential future deep space science missions. Unlike previous radioisotope power supplies for space exploration, such as the passive MMRTG used recently on the Mars Curiosity rover, the ASRG is an active dynamic power supply with moving Stirling engine mechanical components. Due to the long life requirement of 17 years and the dynamic nature of the Stirling engine, the ASRG project faced some unique challenges trying to establish full confidence that the power supply will function reliably over the mission life. These unique challenges resulted in the development of an overall life certification plan that emphasizes long-term Stirling engine test and inspection when analysis is not practical. The ASRG life certification plan developed is described
International R&M/Safety Cooperation Lessons Learned Between NASA and JAXA
Presented are a number of important experiences gained and lessons learned from the collaboration of the National Aeronautics and Space Administration (NASA) and the Japanese Aerospace Exploration Agency (JAXA) on the CoNNeCT (Communications, Navigation, and Networking re-Configurable Testbed) project. Both space agencies worked on the CoNNeCT Project to design, assemble, test, integrate, and launch a communications testbed facility mounted onto the International Space Station (ISS) truss. At the 2012 RAMS, two papers about CoNNeCT were presented: one on Ground Support Equipment Reliability & System Safety, and the other one on combined application of System Safety & Reliability for the flight system. In addition to the logistics challenges present when two organizations are on the opposite side of the world, there is also a language barrier. The language barrier encompasses not only the different alphabet, it encompasses the social interactions; these were addressed by techniques presented in the paper. The differences in interpretation and application of Spaceflight Requirements will be discussed in this paper. Although many, but definitely not all, of JAXA's Spaceflight Requirements were inspired by NASA, there were significant and critically important differences in how they were interpreted and applied. This paper intends to summarize which practices worked and which did not for an international collaborative effort so that future missions may benefit from our experiences. The CoNNeCT flight system has been successfully assembled, integrated, tested, shipped, launched and installed on the ISS without incident. This demonstrates that the steps taken to facilitate international understanding, communication, and coordination were successful and warrant discussion as lessons learned
International R&M/Safety Cooperation Lessons Learned Between NASA and JAXA
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Reliability Quantification of the Flexure: A Critical Stirling Convertor Component
Uncertainties in the manufacturing, fabrication process, material behavior, loads, and boundary conditions results in the variation of the stresses and strains induced in the flexures and its fatigue life. Past experience and the test data at material coupon levels revealed a significant amount of scatter of the fatigue life. Owing to these facts, the design of the flexure, using conventional approaches based on safety factor or traditional reliability based on similar equipment considerations does not provide a direct measure of reliability. Additionally, it may not be feasible to run actual long term fatigue tests due to cost and time constraints. Therefore it is difficult to ascertain material fatigue strength limit. The objective of the paper is to present a methodology and quantified results of numerical simulation for the reliability of flexures used in the Stirling convertor for their structural performance. The proposed approach is based on application of finite element analysis method in combination with the random fatigue limit model, which includes uncertainties in material fatigue life. Additionally, sensitivity of fatigue life reliability to the design variables is quantified and its use to develop guidelines to improve design, manufacturing, quality control and inspection design process is described
Prevalence of hepatitis B and C infection in persons living with HIV enrolled in care in Rwanda
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Proceedings of the fifth international RASopathies symposium: When development and cancer intersect:CONFERENCE REPORT
This report summarizes and highlights the fifth International RASopathies Symposium: When Development and Cancer Intersect, held in Orlando, Florida in July 2017. The RASopathies comprise a recognizable pattern of malformation syndromes that are caused by germ line mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. Because of their common underlying pathogenetic etiology, there is significant overlap in their phenotypic features, which includes craniofacial dysmorphology, cardiac, cutaneous, musculoskeletal, gastrointestinal and ocular abnormalities, neurological and neurocognitive issues, and a predisposition to cancer. The RAS pathway is a well-known oncogenic pathway that is commonly found to be activated in somatic malignancies. As in somatic cancers, the RASopathies can be caused by various pathogenetic mechanisms that ultimately impact or alter the normal function and regulation of the MAPK pathway. As such, the RASopathies represent an excellent model of study to explore the intersection of the effects of dysregulation and its consequence in both development and oncogenesis