A method, apparatus and a system for thermally-assisted pulsed electromagnetic field stimulation for treatment of osteoarthritis are disclosed. The present invention relates to a process for purifying an electroluminescent material, the process involving treating, with an oxidizing agent and then with a column, an electroluminescent material that contains Pd andor P as impurities so as to remove the Pd andor P. The node includes an indication of at least one of the endpoints, and an explicit communication transfer indicator, in a message. The interferometer may be used to measure small vibrations, without pre-calibration andor a feedback servo system for keeping the path-length difference near \u03bb4. The inventive method comprises the following steps: A) blending thermoplastic fibers and reinforcing fibers to give a dry-laid blended web, B) consolidating the blended web by needle felting, C) heating the consolidated blended web, and D) compacting it to give a semi-finished product.