There are provided an apparatus and method for groundwater sampling, using a hydraulic coupler according to the present invention. The beginning of each feed gap is provided with a grinding section, which is followed in the apparatus by a mixing section. A set of previously scheduled events within the source date range is identified. The method also includes forming contact holes for source and drain electrodes to expose a portion of the drain region and expose respective portions of the source region and the edge region contacting the edge portion of the source region; and forming source and drain electrodes. The lens creates a true Fourier transform of the distribution in the optical plane directly on the recording medium. The techniques distribute and redistribute flows of network packets between different paths based on dynamically measured path bandwidth and loads of each flow.