Abstract: An analytical device that can be used to conveniently and accurately assay plural vessels. In one exemplary embodiment, a pair of LED sources provides illumination through a pair of radial waveguides to plural vessels arranged in a pair of substantially concentric and circular rows about the LED sources. A light pipe receives light transmitted through a vessel from each radial waveguide and reflects the received light downward to a single printed circuit board that contains a photodiode for each light pipe, as well as processing circuitry. The first LED source/radial waveguide optical is used to confirm the presence of a vessel, and the second is used to perform, e.g., turbidometric and/or calorimetric assays upon an analyte within the vessel. The vessel is incubated in a vessel support that includes a heat conducting base and a heat insulating cover. Heat is supplied by a DC heater.

Abstract: Described is a system to deliver fluid to a fuel cell. The system includes a source of fluid, a fuel cell and a fluid delivery device in fluid communication therewith. The delivery device includes a pump having a reciprocating piston for drawing fluid from the source, pressurizing the fluid and delivering the fluid to the fuel cell accurately and reproducibly. In a further aspect of the disclosure, there is included a reformer system in fluid communication with an outlet of the pump. The reformer system includes a vaporizer which converts the fluid into a gas thereby generating a back pressure with respect to the pump. The back pressure varies with fluid flow rate and the back pressure also has a random component. The pump accurately and reproducibly delivers the fluid to the vaporizer against such back pressure.