Wavelet Entropy: A New Tool for Edge Detection of Potential Field Data

Subsurface source boundary identification is a major step in the interpretation of potential field anomalies in geophysical exploration. We investigated the behavior of wavelet space entropy over the boundaries of 2D potential field source edges. We tested the robustness of the method for complex source geometries with distinct source parameters of prismatic bodies. We further validated the behavior with two datasets by delineating the edges of (i) the magnetic anomalies due to the popular Bishop model and (ii) the gravity anomalies of the Delhi fold belt region, India. The results showed prominent signatures for the geological boundaries. Our findings indicate sharp changes in the wavelet space entropy values corresponding to the source edges. The effectiveness of wavelet space entropy was compared with the established edge detection techniques. The findings can help with a variety of geophysical source characterization problems

Source depth characterization of potential field data of Bay of Bengal by continuous wavelet transform

195-204Wavelet transform is an efficient technique to interpret the potential field data. The continuous wavelet transform is used to locate and characterize the source of the potential field by transferring the data into an auxiliary space. The technique has been tested on several synthetic source anomalies and applied to potential field data from Bay of Bengal. Using free air gravity and magnetic data the mean depth to causative sources indicates presence of lithospheric flexure at the central part of profile across 85ºE ridge. Using free air gravity data, it is inferred that mean depth to causative sources decreases from west to east across 90E ridge along MAN-01 profile which indicates increase of sediment thickness across the ridge from east to west. The technique gives mean depth of the causative sources without any a priori information which can be used as a initial model in any inversion algorithm

Economic analysis of artificially roughened solar air heater with v-shaped ribs

Due to the minimal transfer of heat from absorber plate to moving air in the duct, solar air heaters have low performance. One of the procedures to augment the heat transfer by substantial amount is by utilizing artificial roughness, by which the performance can be improved considerably. In this study, an economic investigation of solar air heater embedded with artificial roughness is accomplished numerically employing v-shaped roughness, with the objective of optimising life cycle solar savings. The non-dimensional parameters of roughness, namely, angle of attack (α), roughness pitch (p/e) and roughness height (e/Dh) are examined by varying temperature rise over the solar air heater (∆T) and solar radiations (I) for different economic parameters values i.e., cost of collector, cost of roughness elements, and cost of conventional fuel