Abstract: In certain embodiments, a method for proximity determination includes receiving one or more network identifiers, each associated with a corresponding network, from a first mobile device. The method further includes receiving one or more network identifiers, each associated with a corresponding network, from a second mobile device. The method further includes processing the network identifiers received from the first and second mobile devices to determine whether the first mobile device and the second mobile device are in proximity to one another.

Abstract: The present disclosure relates generally to communication services, and more specifically to a system and method for providing communication services to mobile device users. In one example, a method of providing communication services to a plurality of mobile device users includes: entering a first set of data into a data center by a user; processing the first set of data in the data center to generate a second set of data; downloading the second set of data to a first mobile device to form a third set of data to be stored on the first mobile device; and detecting, by the first mobile device, a second mobile device according to the third set of data, and the second mobile device is located within a range of the first mobile device, and communication between the first mobile device and the data center after downloading the second set of data is not required for detecting the second mobile device.

Abstract: A process for recovering pure 2,4,6-trinitrotoluene (TNT) from a crude TNT ixture containing unsymmetrical TNT isomers which comprises forming a homogeneous powder of the crude TNT and silica gel, introducing said powder at the top of a silica gel packed column, and resolving the TNT mixture into its component isomers by contacting said powder with a developing solvent system which is not reactive with the component isomers selected from the group consisting of polar organic solvents, non-polar organic solvents, and mixtures thereof having an energy of adsorption adequate to selectively adsorb the individual TNT isomers, such as a mixture of polar acetonitrile and non-polar trichloro trifluoroethane.