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In some practical problems, the quantity of interest is not the measured
signal, but the power of the measured signal. In electrical engineering,
the measured quantity may be voltage, and for resistive loads power
is proportional to voltage squared. For mechanical vibrations, we
recall energy = force*displacement. So power=force*velocity. For
a viscous damper, force = c * velocity. Thus power dissipated =
c * velocity^2. By similar means we can get a signal
proportional to power by squaring the signal of interest.
$username="comment";
$password="12345aa";
$database="commentsdb1";
$link = mysql_connect('mechanicalvibrationc.domaincommysql.com', 'comments', $password);
if (!$link) {
die('Could not connect: ' . mysql_error());
}
@mysql_select_db($database) or die( "Unable to select database");
$query = "SELECT * FROM `comments` WHERE URL='$URL'";
#echo "query is " . $query;
$result = mysql_query($query);
mysql_close();
while($row = mysql_fetch_array($result)) {
echo "User " . $row['Name'] . " Posted on " . $row['DateTime'];
echo "
";
echo $row['Comment'];
echo "
";
}
echo "
";
?>
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This work by Daniel Kiracofe (daniel dot kiracofe at gmail dot com)
is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.