The US coal industry is undergoing dramatic changes to meet the challenges of a keenly competitive fuels market. Many of these changes involve the application of innovative technology to increase productivity without sacrificing safety. A prime example is longwall mining, which is becoming the accepted method because it allows large blocks of coal to be mined very efficiently.
Lattice methods, namely the lattice Boltzmann method and the lattice spring model, can be successfully used to address acoustic wave propagation in dry and saturated porous media. The resulting code can upscale porous media properties or study direct time simulations in complex media. Only the second application is detailed here for various flat media which contain or not a cavity, which possess uniform properties or not; an explosion is simulated and the accelerations are measured at the surface. The data show that when the medium is simple, the cavity can be easily located, which is not true when it is heterogeneous.
Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights.