19,209 research outputs found
Sensitivity of lunar particle-detection experiments
The use of the Moon as a detector volume for ultra-high-energy neutrinos and
cosmic rays, by searching for the Askaryan radio pulse produced when they
interact in the lunar regolith, has been attempted by a range of projects over
the past two decades. In this contribution, I discuss some of the technical
considerations relevant to these experiments, and their consequent sensitivity
to ultra-high-energy particles. I also discuss some possible future
experiments, and highlight their potential.Comment: To be published in the Proceedings of the ARENA2016 conference,
Groningen, The Netherland
Vietnam: A War with Two Fronts
The Vietnam War is viewed by many historians as a turning point in American war memory. Never before had there been such an outstanding opposition to a military endeavor by the United States\u27 own citizens, government officials, soldiers, and veterans. Drawing from the first hand accounts of PFC Steven Warner and the work of numerous historians, this paper offers an examination into the ways in which some high profile events of the Vietnam War (such as the Cambodia Campaign and the Kent State Shootings) created an environment that negatively impacted United States soldiers and veterans of the Vietnam War
Challenges in Vehicle Safety and Occupant Protection for Autonomous Electric Vertical Take-Off and Landing (eVTOL) Vehicles
The burgeoning electric Vertical Take-off and Landing (eVTOL) vehicle industry has generated a significant level of enthusiasm amongst aviation designers, manufacturers and researchers. This industry is determined to change the urban transportation paradigm from traditional ground-based vehicles (cars, taxis, buses) to air-based eVTOL vehicles which can be summoned, much like how conventional taxi services work currently. These new eVTOL vehicles are designed to be small and lightweight and operate autonomously without user intervention. There are many unknowns as to how the industry will mature. The logistics of creating a completely new category of vehicle along with its own set of rules are complex, and there are many known - and unknown - barriers to overcome. Some (of many) known barriers include airspace management, ground logistics, physical space, and, the vehicle design itself. There are many eVTOL vehicle manufacturers and organizations working these problems presently. This report will focus on one major barrier: the level of safety as it pertains to the framework of eVTOL vehicles. A high level of safety is necessary for the vehicles to gain acceptance as the public adapts to these autonomous ride-sharing services. An overview of current levels of transportation safety and some extrapolation into how eVTOL vehicles might compare is first presented. Next, a discussion categorizing the major differences between Crash Prevention and Crash Mitigation as it pertains to eVTOL vehicle safety is included with identification of current deficiencies. The report then expands into a framework for specific ideas that could use Crash Mitigation to improve vehicle safety through a crashworthy systems level approach with several designs highlighted. Finally, a brief discussion into the regulatory approach and potential guidelines as they pertain to new eVTOL vehicles is presented. Accordingly, much of the supplemental data will be taken from sources pertaining to either General Aviation (GA) aircraft, rotorcraft, or transport category aircraft, due to the lack of overarching data from eVTOL vehicles. As of this writing, the European Aviation Safety Agency has released a draft version of a VTOL Special Condition, with a comment period closing in late 2018. It is assumed that eventual expected operations and anticipated future regulations for VTOL vehicles will consist of some combination of these (and other) sources
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