A plastic leaching chamber has an arch shape cross section, corrugations, and one or more hollow pillars extending downwardly within the interior of the chamber, to support the top of the chamber when the chamber is under load during use. Each gear has a central shaft extending outwardly from the octagear, with the shafts having identical lengths. The outboard rim flange has an annular inner peripheral surface facing the inboard rim flange and an annular outer peripheral surface disposed opposite the inner peripheral surface and facing away from the inboard rim flange. The client applications can invoke a particular service fa\xe7ade to send a message to the network and the invocations can be translated to the native protocols used by the resources in the telecom network to carry out the request. An inlet of a sampling probe is offset from the centerline of the dilution tunnel to a location corresponding to an average particulate matter concentration along a flow profile of a sample mixture to reduce the length of the dilution tunnel. The entire process can be executed automatically.