A technological solution for locating and evaluating resistive targets in a space between a pair of wellbores, at least one of which includes a metallic casing. The solution includes injecting an electric current into the metallic casing of one of the pair of wellbores to energize the metallic casing as a dipole transmitter and leak the current into a formation to form variable electric fields; detecting inside the other wellbore of the pair, by an electric field receiver, the variable electric fields; and measuring, by the electric field receiver, the variable electric fields as a function of time; and generating a resistivity map of the formation based on the measurements of the variable electric fields.

A technological solution for locating and evaluating resistive targets in a space between a pair of wellbores, at least one of which includes a metallic casing. The solution includes injecting an electric current into the metallic casing of one of the pair of wellbores to energize the metallic casing as a dipole transmitter and leak the current into a formation to form variable electric fields; detecting inside the other wellbore of the pair, by an electric field receiver, the variable electric fields; and measuring, by the electric field receiver, the variable electric fields as a function of time; and generating a resistivity map of the formation based on the measurements of the variable electric fields.

A foldable metal detector includes a detection coil disk, a waterproof circuit protecting chamber, a circuit component fixedly disposed in the waterproof circuit protecting chamber, folding fixing components, fastening components, an extending rod fixedly connected to a tail end of the waterproof circuit protecting chamber, and a BLUETOOTH remote control component configured to control the foldable metal detector. The extending rod is manually detachable from the waterproof circuit protecting chamber. The circuit component is electrically connected with the detection coil disk. Brackets are disposed on the detection coil disk. Each bracket includes a first through hole and a second through hole. The fastening components include bolts and fixing columns. Connecting heads with connecting holes are disposed on the waterproof circuit protecting chamber. Each bolt passes through each connecting hole and each first through hole. The bolts are movably connected to the folding fixing components.

A foldable metal detector includes a detection coil disk, a waterproof circuit protecting chamber, a circuit component fixedly disposed in the waterproof circuit protecting chamber, folding fixing components, fastening components, an extending rod fixedly connected to a tail end of the waterproof circuit protecting chamber, and a BLUETOOTH remote control component configured to control the foldable metal detector. The extending rod is manually detachable from the waterproof circuit protecting chamber. The circuit component is electrically connected with the detection coil disk. Brackets are disposed on the detection coil disk. Each bracket includes a first through hole and a second through hole. The fastening components include bolts and fixing columns. Connecting heads with connecting holes are disposed on the waterproof circuit protecting chamber. Each bolt passes through each connecting hole and each first through hole. The bolts are movably connected to the folding fixing components.

A method and system for exploring hidden karst pipelines, mainly comprising: determining an upstream and a downstream of an underground karst pipeline; laying a grounding electrode at the upstream and the downstream respectively; establishing an electromagnetic emission system through underground karst water channels in the underground karst pipeline in a survey area, a transmitter and a generator; arranging a receiving system through an air mobile equipment towing a receiver as a receiving end; turning on the electromagnetic emission system; a generator supplying power to emission circuit; controlling the air mobile equipment to move along routes to collect signal continuously above the survey area, to complete an area-based measurement, and obtain observed data in the whole survey area; processing the observed data; delineating a concrete distribution of the underground karst water channels from the to the, such as a net-shaped path diagram or a tree-shaped path diagram

A method and system for exploring hidden karst pipelines, mainly comprising: determining an upstream and a downstream of an underground karst pipeline; laying a grounding electrode at the upstream and the downstream respectively; establishing an electromagnetic emission system through underground karst water channels in the underground karst pipeline in a survey area, a transmitter and a generator; arranging a receiving system through an air mobile equipment towing a receiver as a receiving end; turning on the electromagnetic emission system; a generator supplying power to emission circuit; controlling the air mobile equipment to move along routes to collect signal continuously above the survey area, to complete an area-based measurement, and obtain observed data in the whole survey area; processing the observed data; delineating a concrete distribution of the underground karst water channels from the to the, such as a net-shaped path diagram or a tree-shaped path diagram

A method includes receiving, from a plurality of magnetic field receivers including magnetic sensors, data characterizing samples obtained by the plurality of magnetic field receivers, the samples of a combination of a first magnetic field and a second magnetic field resulting from interaction of the first magnetic field and an object; determining, using the received data, a polarizability index of the object, the polarizability index characterizing a magnetic polarizability property of the object; classifying, using the determined polarizability index, the object as threat or non-threat; and providing the classification. Related apparatus, systems, techniques, and articles are also described.

A system for passive microwave remote sensing using at least one microwave radiometer includes a fixed body portion and a mobile body portion. The mobile body portion is configured for rotatably coupling with the fixed body portion for rotation about a rotation axis. The mobile body portion is configured for supporting the microwave radiometer therein such that the microwave radiometer rotates about the rotation axis when the mobile body portion is rotated about the rotation axis such that a polarization axis of the radiometer is aligned with an earth axis. The fixed body portion includes a motor mechanism for effecting rotation of the mobile body portion. In an embodiment, the mobile body portion includes a plurality of body section, each body section being configured for supporting a microwave radiometer therein. In another embodiment, each one of the plurality of body sections is configured to be interchangeably coupled with each other.

A system for passive microwave remote sensing using at least one microwave radiometer includes a fixed body portion and a mobile body portion. The mobile body portion is configured for rotatably coupling with the fixed body portion for rotation about a rotation axis. The mobile body portion is configured for supporting the microwave radiometer therein such that the microwave radiometer rotates about the rotation axis when the mobile body portion is rotated about the rotation axis such that a polarization axis of the radiometer is aligned with an earth axis. The fixed body portion includes a motor mechanism for effecting rotation of the mobile body portion. In an embodiment, the mobile body portion includes a plurality of body section, each body section being configured for supporting a microwave radiometer therein. In another embodiment, each one of the plurality of body sections is configured to be interchangeably coupled with each other.

A metal detector 20 includes a detection signal acquisition unit 31, a threshold value setting and updating unit 32, and a determination unit 33. The detection signal acquisition unit 31 acquires a detection signal that changes according to the detection strength for a rebar W1 contained in concrete W, on the surface of the concrete W. The threshold value setting and updating unit 32 sets a threshold value in order to determine the presence or absence of the rebar W1 on the basis of the maximum value and/or the minimum value included in the acquisition results for the detection signal acquired by the detection signal acquisition unit 31. The determination unit 33 determines the presence or absence of the rebar W1 by using the threshold value set in the threshold value setting and updating unit 32.