RESUMO
The potential environmental impact of aromatic and halogenated chemicals from the petrochemical and steel industry is of growning concern. The present paper deals with the modelling and experimental determination of density and speed of sound at the range 278.15-323.15 of six aromatic and halogenated compounds (Benzene, Toluene, Ethylbenzene, Fluorobenzene, 2-Fluorotoluene and Chlorobenzene). Fitting equations were applied to the data in order to correlate for later computer based design. The estimation of the studied properties was made by the application of different theoretical procedures. The Mchaweh-Nasrifar-Moshfeghian model (MNM), an equation of state based on the generalized van der Waals theory which combines the Staverman-Guggenheim combinatorial term of lattice statistics with an attractive lattice gas expression and the Free Length Theory showed a good response at the studied conditions.
Assuntos
Derivados de Benzeno/química , Poluentes Ambientais/química , Hidrocarbonetos Halogenados/química , Ultrassom , Densitometria , Modelos Teóricos , Temperatura , TermodinâmicaRESUMO
Two cases of unilateral ureteral diverticulum are reported, one of which was associated with a bifid ureter. In the first case, this anomaly was incidentally discovered during a urographic work up of a patient with colic nephritis. In the second case, the presenting symptom was hematuria which was finally attributed to ureteral diverticulosis. A structural classification of these anomalous lesions is described, and the commonly associated conditions (obstruction, infection) are reviewed. The authors do not advocate treating these anomalies.