A defect sensing method based on electrical impedance spectroscopy is proposed to image cracks and reinforcing bars in concrete structures. The method utilizes the frequency-dependent behavior of thin insulating cracks: low-frequency electrical currents are blocked by insulating cracks, whereas high-frequency currents can pass through thin cracks to probe the conducting bars. From various frequ...

This invention involves method and apparatus for guiding ablative therapy of abnormal biological electrical excitation. In particular, it is designed for treatment of cardiac arrhythmias. In the method of this invention electrical signals are acquired from passive electrodes, and an inverse dipole method is used to identify the site of origin of an arrhytmia. The location of the tip of the abla...

background: this research studied the feasibility of a simple method for extracting gold from central processing units (cpus) of computer circuit boards without solvent. methods: ceramic and composite cpus of computer circuit boards were used. gold was extracted using a hydrometallurgical method in six stages: grinding of cpus, leaching in nitric acid, leaching in aqua regia, removing the exces...