Sound absorbing boundaries can attenuate noise propagation in a long space, but they may lead the sound field hard to be accurately predicted. This paper presents a coherent image source model for sound field in long spaces with a sound absorbing ceiling. In this model, the reflections on the absorbent boundary are separated from those on reflective ones during applying refection coefficients. ...

Complete debridement and thorough disinfection of infected root canals are considered mandatory for the success of root canal treatment. However, canal preparation and irrigation are not always effective in eliminating total microflora from the root canal system. Traditionally, calcium hydroxide has proven to be an excellent intracanal medicament for infected root canals. However, it is known t...

403 The Journal of The South African Institute of Mining and Metallurgy JULY/AUGUST 2003 Introduction Coal preparation is used to upgrade run-ofmine coal before it is utilized by the end-user, primarily electric utility power plants. According to Fonseca1, the coal preparation process reduces the amount of noncombustible mineral impurities, acid-rain precursor sulphur-bearing minerals and hazar...

polypyrrole (ppy) nanofibers have been fabricated on glassy carbon electrode (gce) usingelectrochemical technique. electropolymerization of pyrrole (py) for the fabrication of ppy nanofiberswas occurred on gce by applying a fixed potential of about 0.85 v for 120 sec in a mild basic solutioncontaining sodium carbonate and sodium perchlorate. in the mild basic media, the monomer, py, isoxidized ...