178 research outputs found
Geometric Unification of Electromagnetism and Gravitation
A recently proposed classical field theory comprised of four field equations
that geometrically couple the Maxwell tensor to the Riemann-Christoffel
curvature tensor in a fundamentally new way is reviewed and extended. The new
theory's field equations show little resemblance to the field equations of
classical physics, but both Maxwell's equations of electromagnetism and
Einstein's equation of General Relativity augmented by a term that can mimic
the properties of dark matter and dark energy are shown to be a consequence.
Emphasized is the emergence of gravity and the unification brought to
electromagnetic and gravitational phenomena as well as the consistency of
solutions of the new theory with those of the classical Maxwell and Einstein
field equations. Unique to the four field equations reviewed here and based on
specific solutions to them are: the emergence of antimatter and its behavior in
gravitational fields, the emergence of dark matter and dark energy mimicking
terms in the context of General Relativity, an underlying relationship between
electromagnetic and gravitational radiation, the impossibility of negative mass
solutions that would generate repulsive gravitational fields or antigravity,
and a method for quantizing the charge and mass of particle-like solutions
NASA Capabilities that Could Impact Terrestrial Smart Grids of the Future
Incremental steps to steadily build, test, refine, and qualify capabilities that lead to affordable flight elements and a deep space capability. Potential Deep Space Vehicle Power system characteristics: power 10 kilowatts average; two independent power channels with multi-level cross-strapping; solar array power 24 plus kilowatts; multi-junction arrays; lithium Ion battery storage 200 plus ampere-hours; sized for deep space or low lunar orbit operation; distribution120 volts secondary (SAE AS 5698); 2 kilowatt power transfer between vehicles
Modification of Sand Fly Biting Behavior by \u3ci\u3eLeishmania\u3c/i\u3e Leads to Increased Parasite Transmission
To attempt rodent-sand fly-rodent transmission of Leishmania major, laboratory-reared Phlebotomus doboscqi were fed on L. major-infected mice and then refed on uninfected mice 21 days later. Flies which refed either probed 1–2 times and took a full blood meal in less than 10 minutes or probed 3 or more times and took little or no blood during a period of 15 minutes or more. When dissected, 7 of 8 flies which experienced difficulty in obtaining a blood meal had flagellates in their cibaria, an observation supporting the hypothesis that parasites in this part of the alimentary canal modify normal blood feeding behavior. None of the infected females which probed 1–2 times had similar anterior station infections. Infected sand flies transmitted L. major to uninfected mice and a single fly, transferred from 1 mouse to the next while repeatedly attempting to take blood, infected 5 mice.
During a year-long survey in Baringo District, Kenya, we collected 9,182 female sand flies. Only 2 of the 278 P. duboscqi captured during this collection were infected with L. major; however, 18 of the 789 small rodents from this area were infected with L. major. Parasite interference with normal blood feeding may explain how a relatively small population of P. duboscqi, only a few of which are infected with L. major, can amplify parasite transmission thereby maintaining a disproportionately large reservoir in local rodents
Series Connected Converter for Control of Multi-Bus Spacecraft Power Utility
The invention provides a power system using series connected regulators. Power from a source, such as a solar array, is processed through the regulators and provided to corresponding buses used to charge a battery and supply loads. The regulators employ a bypass loop around a DC-DC converter. The bypass loop connects a hot input of the converter to a return output, preferably though an inductor. Part of the current from the source passes through the bypass loop to the power bus. The converter bucks or boosts the voltage from the source to maintain the desired voltage at the bus. Thus, only part of the power is processed through the converter. The converter can also be used without the bypass loop to provide isolation. All of the converters can be substantially identical
High Voltage Hybrid Electric Propulsion (HVHEP) Activity
This presentation discusses the High Voltage Hybrid Electric Propulsion (HVHEP) Activity
Overview of NASA Power Technologies for Space and Aero Applications
To achieve the ambitious goals that NASA has outlined for the next decades considerable development of power technology will be necessary. This presentation outlines the development objectives for both the space and aero applications. It further looks at the various power technologies that support these objectives and examines drivers that will be a driving force for future development
Proposal and Development of a High Voltage Variable Frequency Alternating Current Power System for Hybrid Electric Aircraft
The development of ultra-efficient commercial vehicles and the transition to low-carbon emission propulsion are seen as thrust paths within NASA Aeronautics. A critical enabler to these paths comes in the form of hybrid-electric propulsion systems. For megawatt-class systems, the best power system topology for these hybrid-electric propulsion systems is debatable. Current proposals within NASA and the Aero community suggest using a combination of AC and DC for power transmission. This paper proposes an alternative to the current thought model through the use of a primarily high voltage AC power generation, transmission, and distribution systems, supported by the Convergent Aeronautics Solutions (CAS) Project. This system relies heavily on the use of dual-fed induction machines, which provide high power densities, minimal power conversion, and variable speed operation. The paper presents background on the project along with the system architecture, development status and preliminary results
Beamed-Energy Propulsion (BEP) Study
The scope of this study was to (1) review and analyze the state-of-art in beamed-energy propulsion (BEP) by identifying potential game-changing applications, (2) formulate a roadmap of technology development, and (3) identify key near-term technology demonstrations to rapidly advance elements of BEP technology to Technology Readiness Level (TRL) 6. The two major areas of interest were launching payloads and space propulsion. More generally, the study was requested and structured to address basic mission feasibility. The attraction of beamed-energy propulsion (BEP) is the potential for high specific impulse while removing the power-generation mass. The rapid advancements in high-energy beamed-power systems and optics over the past 20 years warranted a fresh look at the technology. For launching payloads, the study concluded that using BEP to propel vehicles into space is technically feasible if a commitment to develop new technologies and large investments can be made over long periods of time. From a commercial competitive standpoint, if an advantage of beamed energy for Earth-to-orbit (ETO) is to be found, it will rest with smaller, frequently launched payloads. For space propulsion, the study concluded that using beamed energy to propel vehicles from low Earth orbit to geosynchronous Earth orbit (LEO-GEO) and into deep space is definitely feasible and showed distinct advantages and greater potential over current propulsion technologies. However, this conclusion also assumes that upfront infrastructure investments and commitments to critical technologies will be made over long periods of time. The chief issue, similar to that for payloads, is high infrastructure costs
Lessons Learned From Developing Advanced Space Power Systems Applied to the Implementation of DC Terrestrial Micro-Grids
No abstract availabl
Overview of Intelligent Power Controller Development for Human Deep Space Exploration
Intelligent or autonomous control of an entire spacecraft is a major technology that must be developed to enable NASA to meet its human exploration goals. NASA's current long term human space platform, the International Space Station, is in low earth orbit with almost continuous communication with the ground based mission control. This permits the near real-time control by the ground of all of the core systems including power. As NASA moves beyond Low Earth Orbit, the issues of communication time-lag and lack of communication bandwidth beyond geosynchronous orbit does not permit this type of operation. This paper presents the work currently ongoing at NASA to develop an architecture for an autonomous power control system as well as the effort to assemble that controller into the framework of the vehicle mission manager and other subsystem controllers to enable autonomous control of the complete spacecraft. Due to the common problems faced in both space power systems and terrestrial power system, the potential for spin-off applications of this technology for use in micro-grids located at the edge or user end of terrestrial power grids for peak power accommodation and reliability are described
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