The acetylation of various alcohols and phenols was performed successfully using acetic anhydride in the presence of Citric acid coated magnetite nanoparticles as catalyst under solvent-free condition and at 45 °C. The catalyst showed high thermal stability and was recovered and reused at least 5 times without any considerable loss of activity. The present process is environmentally benign and ...

a real-time optimization (rto) strategy incorporating the fuzzy sets theory is developed, where the problem constraints obtained from process considerations are treated in fuzzy environment. furthermore, the objective function is penalized by a fuzzified form of the key process constraints. to enable using conventional optimization techniques, the resulting fuzzy optimization problem is then re...

Since the work of André Martinet back in the 60’s [7], the notion of ‘economy’ has been accepted as one of the main principles underlying the organization of phonological inventories (hereafter PI). This principle, also named MUAF (‘Maximal Use of Available Features’) by John Ohala [8], states that PI are organized along a few phonetic dimensions that they tend to maximize in terms of number of...

Natural gas produced at high pressure (50-70 bar) is the only industrial source of helium (He). A membrane separation process may offer a more efficient production system with smaller footprint and lower operational cost than conventional cryogenic system. Inorganic membranes with high mechanical strength are known to exhibit good stability at high pressure. In this work, two inorganic membrane...

the photocatalytic decomposition of trichloroethylene (tce) and tetrachloroethylene (pce)in water was studied. tce and pce were present in water at very low concentrations of about 15 μg/dm3. thisconcentration level corresponds to the one occasionally occurring in groundwater. results of this researchconfirmed usefulness of the photocatalytic process for successful removal of low-concentrated t...