Archive for luty, 2008

Free cPanel Web Hosting with PHP5/Mysql

wtorek, luty 26th, 2008

Free cPanel Web Hosting with PHP5/Mysql - no advertising!
Register now: http://www.000webhost.com/?id=24705

We can offer you a free web hosting package packed with advanced features for hosting & building professional dynamic websites. We provide secure free web space with all the web hosting tools you could possibly ever need.

Our package includes:
- 250 MB of Disk Space, 100 GB Bandwidth
- Host your own domain (http://www.yourdomain.com)
- cPanel Powered Hosting (you will love it)
- Over 500 website templates ready to download
- Free POP3 Email Box with Webmail access
- FTP and Web based File Manager
- PHP, MySQL, Perl, CGI, Ruby.
- And many more..

Click here to visit us: http://www.000webhost.com/?id=24705

The op-amp gain calculated

wtorek, luty 26th, 2008

The op-amp gain calculated at DC does not apply at higher frequencies. To a first approximation, the gain of a typical op-amp is inversely proportional to frequency. This means that an op-amp is characterized by its gain-bandwidth product. For example, an op-amp with a gain bandwidth product of 1 MHz would have a gain of 5 at 200 kHz, and a gain of 1 at 1 MHz. This low-pass characteristic is introduced deliberately, because it tends to stabilize the circuit by introducing a dominant pole. This is known as frequency compensation.

Modern wire rope

czwartek, luty 21st, 2008

Modern wire rope was invented by the German mining engineer Wilhelm Albert in the years between 1831 and 1834 for use in mining in the Harz Mountains in Clausthal, Lower Saxony, Germany. It was quickly accepted because it proved superior to ropes made of hemp or to metal chains, such as had been used before.

Wilhelm Albert’s first ropes consisted of wires twisted about a hemp rope core, six such strands then being twisted around another hemp rope core in alternating directions for extra stability. Earlier forms of wire rope had been made by covering a bundle of wires with hemp.

In America wire rope was later manufactured by John A. Roebling, forming the basis for his success in suspension bridge building. Roebling introduced a number of innovations in the design, materials and manufacture of wire rope.

Manufacturing a wire rope is similar to making one from natural fibres. The individual wires are first twisted into a strand, then six or so such strands again twisted around a core. This core may consist of steel, but also of natural fibres such as sisal, manila, henequen, jute, or hemp. This is used to cushion off stress forces when bending the rope.

This flexibility is particularly vital in ropes used in machinery such as cranes or elevators as well as ropes used in transportation modes such as cable cars, cable railways, funiculars and aerial lifts. It is not quite so essential in suspension bridges and similar uses.

Wire rope is often sold with vinyl and nylon coatings. This increases weather resistance and overall durability, however it can lead to weak joints if the coating is not removed correctly underneath joints and connections.