12 research outputs found
Performance Effects of Adding a Parallel Capacitor to a Pulse Inductive Plasma Accelerator Powertrain
Pulsed inductive plasma accelerators are electrodeless space propulsion devices where a capacitor is charged to an initial voltage and then discharged through a coil as a high-current pulse that inductively couples energy into the propellant. The field produced by this pulse ionizes the propellant, producing a plasma near the face of the coil. Once a plasma is formed if can be accelerated and expelled at a high exhaust velocity by the Lorentz force arising from the interaction of an induced plasma current and the magnetic field. While there are many coil geometries that can be employed to inductively accelerate a plasma, in this paper the discussion is limit to planar geometries where the coil take the shape of a flat spiral. A recent review of the developmental history of planar-geometry pulsed inductive thrusters can be found in Ref. [1]. Two concepts that have employed this geometry are the Pulsed Inductive Thruster (PIT) and the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)
NASA Ares I Launch Vehicle Upper Stage Reaction Control System (ReCS) Cold Flow Development Test Overview
NASA s Ares I launch vehicle, consisting of a five segment solid rocket booster first stage and a liquid bi-propellant J2-X engine Upper Stage, is the vehicle that s been chosen to launch the Orion Crew Module, which will return humans to the Moon, Mars, and beyond. After First Stage booster separation, the Reaction Control System (ReCS), a monopropellant hydrazine system, will provide the Upper Stage element with three degrees of freedom control as needed. This paper provides an overview of the system level development testing that has taken place on the Ares I launch vehicle Upper Stage ReCS. The ReCS System Development Test Article (SDTA) was built as a flight representative water flow test article whose primary test objective was to obtain fluid system performance data to evaluate the integrate system performance characteristics and verify analytical models. Water is the industry standard for cold flow testing of hydrazine systems, because the densities are very close and the speeds of sound are well characterized. The completion of this development level test program was considered necessary to support the ReCS Critical Design Review. This paper will address the design approach taken in building the test article, the objectives of the test program, types of testing completed, general results, the ability of the program to meet the test objectives, and lessons learne
NASA's Centennial Challenges Program
Why Centennial Challenges? The program was established to conduct prize competitions in support of the Vision for Space Exploration and ongoing NASA programs
Development of a Novel Live Attenuated Influenza A Virus Vaccine Encoding the IgA-Inducing Protein
Live attenuated influenza virus (LAIV) vaccines elicit a combination of systemic and mucosal immunity by mimicking a natural infection. To further enhance protective mucosal responses, we incorporated the gene encoding the IgA-inducing protein (IGIP) into the LAIV genomes of the cold-adapted A/Leningrad/134/17/57 (H2N2) strain (caLen) and the experimental attenuated backbone A/turkey/Ohio/313053/04 (H3N2) (OH/04att). Incorporation of IGIP into the caLen background led to a virus that grew poorly in prototypical substrates. In contrast, IGIP in the OH/04att background (IGIP-H1att) virus grew to titers comparable to the isogenic backbone H1att (H1N1) without IGIP. IGIP-H1att- and H1caLen-vaccinated mice were protected against lethal challenge with a homologous virus. The IGIP-H1att vaccine generated robust serum HAI responses in na茂ve mice against the homologous virus, equal or better than those obtained with the H1caLen vaccine. Analyses of IgG and IgA responses using a protein microarray revealed qualitative differences in humoral and mucosal responses between vaccine groups. Overall, serum and bronchoalveolar lavage samples from the IGIP-H1att group showed trends towards increased stimulation of IgG and IgA responses compared to H1caLen samples. In summary, the introduction of genes encoding immunomodulatory functions into a candidate LAIV can serve as natural adjuvants to improve overall vaccine safety and efficacy
Rights of Pachamama: The emergence of an earth jurisprudence in the Americas
Earth jurisprudence represents an alternative approach to the law based on the belief that nature has rights. In this view, a river has the right to flow, species have the right to continue to exist in the wild, and ecosystems have the right to adapt and evolve over time. Proponents of Earth jurisprudence argue that, by treating nature as exploitable resources, contemporary legal systems actively promote environmental harms. Recognising rights of nature, they argue, will transform core values and inspire social changes that promote economic development which respects nature鈥檚 limits. Since 2006, rights of nature have been recognised by some sub-federal public bodies in the United States and by the governments of Ecuador and Bolivia. This paper sets out to answer two questions. First, what explains the legal recognition of rights of nature in Ecuador and Bolivia? Second, what factors impede a wider adoption and implementation of Earth jurisprudence? Amongst the constraints, it will be argued, is that Ecuador and Bolivia continue to pursue an extractivist economic development model, with assertions of national sovereignty over natural resources tending to prevail over Earth jurisprudence and environmental conservation