Embodiments of the present invention are directed to security systems for securing an item of merchandise from theft. Each heat engine includes a heat exchanger disposed near the bottom of the solar pond, a working fluid boiler at least partially submerged in the solar pond, a turbine-generator, and a working vapor condenser disposed under the solar pond in the open-ended chamber. The conjugates of the invention further comprise therapeutic agents such as proteins, peptides, nucleosides, nucleotides, antiviral agents, antineoplastic agents, antibiotics, etc. If the passenger name record includes a corporate identifier, corporate value data is determined, and an availability request that includes the corporate identifier and the corporate value data is communicated to at least one inventory system associated with the at least one travel inventory item. Moreover, when the electrical resistance of at least one of the bifilar conductors is known as a function of temperature, this arrangement allows one to sense the temperature of a workpiece supported on the substrate. The source may receive the request, retrieve the desired information, and transmit it to the requesting entity.