well, to get anything to show up in your browser from PHP, you have to echo or print it to the browser, with proper quotes:
print '<td align="center">'.$v.'</td>';
or if you don't like single quotes, you can use doubles throughout, but you have to escape the inside quotes with a \ like so:
print "<td align=\"center\">".$v."</td>";
The periods are used for concatenation, and you could break this statement apart anywhere, and concatenate it using the dot method. Just make sure you have your spacing right.
cheers!