Impact energy vulnerability

The incidence of aircraft impacts may be significantly higher in certain areas (e g., in the vicinity or airports). The aircraft crash hazard is site specific and tlie failure is strongly dependent on the kinetic energy of tlie aircraft. Two types of data are needed to analyze for aircraft impact the aircraft crash rate in tlie site vicinity (per unit area per year) and tlie effective target area of tlie vulnerable item. Crash rates for different categories of aircraft can be obtained from state and national autliorities (e.g., FAA). The proximity of the site to airfields must be taken into account because crashes are much more frequent witliin a radius of approximately 3 miles. 

Primary energy supply is a key issue for any new transportation fuel. Constraints on domestic resources and production of petroleum have led to increasing levels of imports. An important policy driver for alternative fuels for transportation in the USA is that they will alleviate some of the issues surrounding dependence and economic vulnerability related to petroleum imports, especially from politically unstable parts of the world. This raises some important questions for hydrogen as a future alternative fuel will the USA have the resources to produce hydrogen for vehicles at low cost and with low environmental impact ... 

The agro-eeosystem is vulnerable to attaeks by terrorists which can narrow the margins between safe and unsafe practices. For example, the tacties used by terrorists ean have huge impacts on foodstuffs and feedstuffs and ean be as simple as, for example, disrupting the distribution of electrieal and fossil fuel energy. For example. 

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