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Nasa Mars Exploration – triple redundancy

Systems Classification

Concerning the redundancy of all mission equipment, we have adhered to NASA policy requiring double redundancy for all mission critical factors and triple redundancy for all life critical factors. The redundancies are most clearly explained by breaking down the entire mission into two different phases, transport and surface. We define a transport phase to be any period of time spent traveling to or from mars, for example the T.M.I. journey. The surface phase is simply the period of time spent inhabiting the mars surface.

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List of Threes in Anatomy

The structure of the human body is organized into groups of three with remarkable frequency. I have listed several examples of this tendency by region. This list does not include structures contributing to form the many “triangles” in the body. If you know of any more, please let me know.

John A. McNulty, Ph.D.

Historically, this was the first hyperlink to the Book of Threes in 1996 thanks to John McNulty . . .

Michael Eck – Author The Book of Threes

To visit John McNulty’s amazing list, click here.

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RCA – RADIO CLUB OF AMERICA

(Adapted from "The Twenty-fifth Anniversary Year Book", The Radio Club of America, Inc., 1934)

A HISTORY OF THE
RADIO CLUB OF AMERICA, Inc.
by: George E. Burghard

_________

The story of the Radio Club of America begins over a quarter of a century ago, during the really dark ages of the radio art, about 1907

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The Sierpinski Triangle

The Sierpinski TriangleStep One Draw an equilateral triangle with sides of 2 triangle lengths each. Connect the midpoints of each side. How many equilateral triangles do you now have? Image Shade out the triangle in the center. Think of this as cutting a hole in the triangle. Image Continue reading The Sierpinski Triangle

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The KnotPlot Site – trefoil

Trefoil Knot“Here you will find a [browsable] collection of knots and links, viewed from a (mostly) mathematical perspective. Nearly all of the images here were created with KnotPlot, a fairly elaborate program to visualize and manipulate mathematical knots in three and four dimensions.” The diagrams are in color and are exceptionally clear.

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The K-8 Aeronautics Internet Textbook

The principles of aeronautics for elementary and middle school children, presented in three levels in English and Spanish for beginning, intermediate, and advanced students. Curriculum Bridges provides activities that show the relationships between aeronautics and math, language arts, social studies, visual/performing arts, and literature. Includes a basic Internet tutorial, lesson plans, an animated sign language dictionary, the Wright brothers, descriptions of careers, and Tennis Science.

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Lithium – Periodic Table – element 3

LithiumLithium is a Group 1 (IA) element containing just a single valence electron (1s22s1). Group 1 elements are called "alkali metals". Lithium is a solid only about half as dense as water. A freshly cut chunk of lithium is silvery, but tarnishes in a minute or so in air to give a grey surface.

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Kepler’s Three Laws of Planetary Motion

keplerThe laws were formulated between 1609 to 16l9, and are (as usually stated):

    <ul>   <li> Planets move around the Sun in <strong>ellipses</strong>, with the Sun at one focus    </li>   <li> The line connecting the Sun to a planet sweeps <strong>equal areas in equal times. </strong></li>   <li> The<strong> square</strong> of the orbital period of a planet is proportional to the                                                              <strong> cube</strong> (3rd power) of the mean distance from the Sun in     (or in other words--of the&quot;semi-major axis&quot; of the ellipse, half the sum of smallest      and greatest distance from the Sun)      </li> </ul>   <ol>  </ol> <!--more--> <a href="http://www-spof.gsfc.nasa.gov/stargaze/Kep3laws.htm" target="_blank" rel="noopener noreferrer">Read more . . .</a><br />
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From Stargazers to Starships

This high-school level tutorial focuses on three topics: Astronomy of the Earth's motion in space, which includes information, and some experiments and projects that teach concepts about the calendar, seasons, Kepler's laws, building a sundial, and more; Newtonian mechanics, which ha understanding Newton's laws and discussion of mass and motion; and Spaceflight and Spacecraft. Includes a timeline, a list of concepts covered, and a glossary.

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Clock

Clocks

How long is a day?
It's the amount of time it takes for the Earth to rotate one time on its axis. But how long does it take the Earth to rotate? That is where things become completely arbitrary. The world has decided to standardize on the following increments:

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Third Molar – Wisdom Teeth

Adult humans typically have 32 teeth Continue reading Third Molar – Wisdom Teeth

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Teeth

Kinds of teeth

Human beings grow two sets of teeth: (1) deciduous teeth and (2) permanent teeth.

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