Rinker Materials Corporation.
Rinker Group
http://www.rinkermaterials.com/ProdsServices/ConcretePipe/default.shtml

Perma-Pipe, Inc.
Manufactures pre-insulated pipe and double containment pipe for the oil and gas industry. Also offer leak detection and location, heat traced cathodic protection systems and pipe inspection services.
http://www.permapipe.com/

No-Dig-Pipe, Microtunneling Clay Pipe
No-Dig, A Division of MCP Industries Inc is the manufacturer of the first rigid bodied, clay pipe for use in microtunneling, sliplining, pipe bursting and in casings in the United States. Our first installation was in Houston Texas in April 1992. Since that time, over 70,000 linear feet of NO-DIG pipe have been installed.
http://www.no-dig-pipe.com/

Clow Water Systems Pipe and Fittings
Clow Water Systems Company has been one of the United States premiere manufacturers of iron pipe and fittings in the waterworks industry.
http://www.clowwatersystems.com

Avon Barrier Company
We offer a wide range of vehicle and pedestrian access control systems such as parking barriers, road blockers, gate systems, turnstiles, high security equipment and revenue systems
http://www.avon-barrier.co.uk/

EU Trade Barriers Kill
A study demonstrating how the trade barriers of EU affect the poor countries, published by the Centre for the New Europe.
http://www.cne.org/pub_pdf/2003_09_04_EU_barriers_kill.pdf

Barriers & Bollards Limited
Bollards, Bollard Systems, Steel Bollards, Security Bollards by Barriers and Bollards Limited, manufacturers, suppliers and installers.
http://www.barriersandbollards.com/

Tunneling
Addresses the phenomenon of quantum tunneling. Presents animations of the scattering of a particle from two-dimensional potential barriers and wells, as well as from barriers with slits.
http://rugth30.phys.rug.nl/quantummechanics/tunnel.htm

Liberty and Rocky Mountain Pipe
Liberty Pipe Companies supplies, designs, manufactures, fabricates, and installs equestrian, livestock and estate fencing and buildings. Performance Pipe Products, Fencing, Pipe, and Asset Recovery.
http://www.libertypipe.com/

Star Pipe Products
Star Pipe Products; a manufacture of ductile iron fittings, joint restraints, construction and municipal castings, AWWA grooved products, soil pipe and related products.
http://www.starpipeproducts.com