Abstract: In the preferred embodiment of the present invention a passive, wireless, RFID-based wireless buckle-closure sensor determines whether the buckle of a child safety seat is secured. Sensors also are provided to determine if the child is in the seat, the temperature and if the vehicle is in operation, and alarms are sounded if an unsafe condition is detected by the system. Child safety seats utilize a 3-point or 5-point locking-mechanism for seat belt and harness restraints. The locking-mechanism requires that metal belt/harness components latch together and are released by depression of a lock-mounted release button. In the preferred embodiment of the present invention a passive RF transponder is affixed to the buckle. Essentially the RF transponder comprises an RFID device without a data component. The RF transponder is interrogated by a frequency-scanning reader, which determines the resonant frequency of the transponder.

Abstract: Disclosed herein is a method of determining the fracture geometry of a subterranean fracture comprising introducing into the fracture a target particle and/or proppant; transmitting into the fracture electromagnetic radiation having a frequency of about 300 megahertz to about 100 gigahertz; and analyzing a reflected signal from the target particle to determine fracture geometry. Disclosed herein too is a method of determining the fracture geometry of a subterranean fracture comprising introducing into the fracture a target particle and/or proppant; wherein the target particle and/or proppant comprises a high dielectric constant ceramic having a dielectric constant of greater than or equal to about 2; transmitting into the fracture electromagnetic radiation having a frequency of less than or equal to about 3 gigahertz; and analyzing a reflected signal from the target particle and/or proppant to determine fracture geometry.