This work presents a comparative study among three linearization schemes widely used in petroleum reservoir simulation, namely the Implicit Pressure Explicit Saturation (IMPES), Fully Implicit (FI) and Adaptive Implicit Method (AIM). Attention is given to the criterion used for switching from IMPES to FI and vice-versa. The black-oil model considering the oil-water flow is employed. The equations are discretized using an unstructured Voronoi mesh in a finite-volume framework. The numerical results are analyzed based on the number of iterations in the Newton and solver procedures, number of implicit volumes, and mass balance error of components. The effect of the stopping criterion on Newton's iterations is also investigated. The outcome of the study reveals that adaptive implicit methodologies can be a good choice when unstructured grids are present, allowing the use of time steps with the same order of magnitude as the ones used in FI procedures, but with reduction in the computational effort.

Determinou-se a taxa de filtração glomerular por meio do EDTA, marcado com 51Cr e com 113mIn, pela técnica de injeção única, em nove equinos, seis machos e três fêmeas com idades de dois a 12 anos. A taxa de filtração glomerular foi calculada a partir da curva de desaparecimento no plasma e do volume de distribuição do radiotraçador, 51Cr-EDTA ou 113mIn-EDTA. O resultado (média±desvio-padrão) foi de 148,80±26,42mL.min-1.100kg. Conclui-se que a medida da taxa de filtração glomerular pelo 51Cr-EDTA ou 113mIn-EDTA, pela técnica de injeção única, elimina o cateterismo vesical e, por sua simplicidade, comodidade, precisão e baixa dose de radiação, pode ser empregada em cavalos como método de escolha em rotina clínica.

The glomerular filtration rate was determined in nine healthy horses, six male and three female, aged two to 12-year-old, by means of 51Cr and 113mIn labeled EDTA single injection technique. The glomerular filtration rate was calculated from the plasma disappearance curve and the volume of distribution of the radiotracer, 51Cr-EDTA or 113mIn-EDTA. The result (mean±standard deviation) was 148.80±26.42mL.min-1.100kg. It is concluded that the measurement of glomerular filtration rate by 51Cr-EDTA or 113mIn-EDTA by single injection technique eliminates the bladder catheterization, and for its simplicity, convenience, accuracy, and low dose of radiation, can be used in horses as a method of choice in clinical routine.

Corpos de prova de aço inoxidável ISO 5832-1 foram nitretados em uma atmosfera de 90% vol. N2 e 10% vol. H2, a uma temperatura de 630º C. Os tempos de processamento estudados foram 1, 3 e 5 h. Utilizaram-se as seguintes técnicas de análise: difração de raios-x (DRX), microscopia eletrônica de varredura (MEV) e microdureza Vickers, além da análise da variação de massa. Os resultados evidenciaram o crescimento não difusivo da camada de compostos. O aumento do tempo, de 1 para 3 h, promove uma maior incorporação de nitrogênio na superfície do material promovendo a formação de fases mais ricas nesse elemento. Promove também o aumento da dureza e do ganho de massa, bem como crescimento da camada nitretada. Os processamentos realizados por 3 e 5 h apresentam resultados similares. Isto se deve à formação de uma camada superficial rica em nitretos que dificulta a entrada do nitrogênio para o interior da amostra.

Samples of stainless steel ISO 5832-1 were nitrided in gas mixture of 90% N2 and 10% H2 at a temperature of 630º C. The treatment time was selected in 1, 3 and 5 hours. Treated samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vickers microhardness, besides the analysis of the mass variation. The results evidence the no diffusion growth of the compound layer. The increase time, of 1 for 3h, to cause a larger incorporation of nitrogen in the surface of the material accompanied of formation the richer phases in that element. Also cause the increase of hardness and mass, as well as growth of the nitrided layer. The processing accomplished by 3 and 5 h present similar results. This is due the formation of a rich superficial layer in nitrites that inhibits the entrance of nitrogen for the interior of the sample.

The present study was carried out at the Army Central Hospital, Rio de Janeiro, Brazil, from September 2000 to December 2001, employing diethylenetriamine penta-acetic acid labeled with technetium-99m (99mTc-DTPA) to evaluate the renal function of nineteen symptomatic patients infected with S. haematobium during a peace mission in Mozambique. Results evidenced that the most frequent clinical manifestations were hematuria (68.4%) and low back pain (68.4%) and 73.7% patients had altered dynamic renal scintigraphy expressed by an increase in the excretory phase independently of the symptoms duration; furthermore, none of them had mechanical obstructive pattern. Schistosoma haematobium glomerulopathy could be considered a pathological finding without correlation with the disease clinical manifestations.