In one embodiment, a processor-readable medium stores code representing instructions that when executed by a processor cause the processor to receive a selected destination to which to send a job of a particular type, and pass the job, including the selected destination as a job parameter, to a job engine whose function matches the particular job type. A tri-truss assembly may provide stability and support to a gate that is part of a portable or temporary fencing system. A novel sample structure and a novel use of a milling pattern allow the creation of STEM samples as thin as 50 nm without significant bowing or warping. The set of shear ties may extend from the rib and have a set of elongate members in which the set of elongate members are attached to the plurality of stringers. The first multi-frequency impedance controller includes a set of band pass filters connected in parallel and tuned to said first set of frequencies to be admitted, and a set of notch filters connected in series and tuned to said first set of frequencies to be blocked.