in this research work, the dissolution of chalcopyrite was investigated under atmospheric pressure, with sulfate media at low temperatures, in 30°c to 50°c. in the galvanic interaction between chalcopyrite and pyrite, pyrite is used as a leaching catalyst. effects of different parameters such as temperature, stirring speed, pyrite to chalcopyrite ratio, particle size, and solution potential wer...

a refrigeration cycle is a chain of various pieces of equipment including compressors, condensers, evaporators, and expansion devices each of which takes on a particular thermodynamic process duty in the cycle that eventually results in the production of the required refrigeration. the results of optimized mixed refrigerant cycles (mrcs) in part i show that the configuration of mrc is an effect...

Plants activate antioxidant defense mechanisms under stress, which help maintaining the structural integrity of cell components and possibly reduces oxidative damage.  Low temperature stress leads to the production of reactive oxygen species and oxidative damage to plants. In this study, the effect of putrescine and proline on reducing the production of reactive oxygen species and increasing th...

Since the first report of ultraviolet lasing from ZnO nanowires, substantial effort has been devoted to the development of synthetic methodologies for one-dimensional ZnO nanostructures. Among the various techniques described in the literature, evaporation and condensation processes are favored for their simplicity and high-quality products, but these gas-phase approaches generally require econ...

BACKGROUND Calcium phosphate manufactured samples, prepared with hydroxyapatite, are used as either spacers or fillers in orthopedic surgery, but these implants have never been used under conditions of mechanical stress. Similar conditions also apply with cements. Many authors have postulated that cements are a useful substitute material when implanted in vivo. The aim of this research is to de...