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Contents contributed and discussions participated by dpurdy

dpurdy

A Danielson Diigo Group - 77 views

Danielson highly_effective
started by dpurdy on 28 Feb 14 no follow-up yet
  • dpurdy
     
    I created a group so teachers can share strategies that meet highly effective category in the Danielson Rubric. Lets work together and share rather than compete and keep our ideas to ourselves.

    https://groups.diigo.com/group/danielson
dpurdy

How to become "Highly Effective" with Danielson | Diigo - Groups - 140 views

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    Leave comments and links to highly effective methods you have used or ideas that represent the best practices. This will be a group that shares our journey to become a better teacher through the use of the Danielson Rubric. The RTTT performance review system lacks a way to share best practices so people can improve their teaching. This is an attempt to solve that problem.
dpurdy

Hydrogen vehicle - Wikipedia, the free encyclopedia - 13 views

    • dpurdy
       
      Is hydrogen sustainable? depends on the source. see this highlight.
  • While methods of hydrogen production that do not use fossil fuel would be more sustainable
  • The challenges facing the use of hydrogen in vehicles include production, storage, transport and distribution.
  • ...3 more annotations...
  • The hydrogen infrastructure consists mainly of industrial hydrogen pipeline transport and hydrogen-equipped filling stations like those found on a hydrogen highway. Hydrogen stations which are not situated near a hydrogen pipeline can obtain supply via hydrogen tanks, compressed hydrogen tube trailers, liquid hydrogen tank trucks or dedicated onsite production.
  • Hydrogen use would require the alteration of industry and transport on a scale never seen before in history. For example, according to GM, 70% of the U.S. population lives near a hydrogen-generating facility but has little access to hydrogen, despite its wide availability for commercial use.[64] The distribution of hydrogen fuel for vehicles throughout the U.S. would require new hydrogen stations that would cost, by some estimates approximately 20 billion dollars[65] and 4.6 billion in the EU.[66] Other estimates place the cost as high as half trillion dollars in the United States alone.[67]
  • Hydrogen fuel does not occur naturally on Earth and thus is not an energy source, but is an energy carrier. Currently it is most frequently made from methane or other fossil fuels. However, it can be produced from a wide range of sources (such as wind, solar, or nuclear) that are intermittent, too diffuse or too cumbersome to directly propel vehicles. Integrated wind-to-hydrogen plants, using electrolysis of water, are exploring technologies to deliver costs low enough, and quantities great enough, to compete with traditional energy sources.[2]
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    Fuel cell cars are expensive.  The fuel cell costs a lot
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