The Promoting Role of W in Nickel Based Catalyst for Bi-Reforming.

In the present study, co-impregnated tungsten and silver onto nickel based catalysts have been investigated. The influences caused by tungsten modification were inspected by XRD, XPS, TPR and TEM with Elemental Mapping from SEM. the result revealed similarity in terms of physicochemical properties. By adding trace of tungsten subsidiary to silver, it was able to reach as high performance as the catalyst with silver only. The modified catalysts showed enhanced stability and reactivity by forming large Al2O3 structure.

Effect of Tungsten Addition on Nickel-Based Catalyst for Combined Steam and CO2 Reforming of Methane.

In this study, we investigated the effect of tungsten addition on Ni-based catalyst in methane steam-CO2 reforming. All the catalysts were prepared by the co-impregnation method with varied tungsten loading. The as-prepared catalysts were characterized by inductively coupled plasma atomic emission spectrometer, X-ray diffraction, temperature-programmed reduction and thermogravimetric analysis. The tungsten-loaded catalyst showed improved coke resistance and CO2 reactivity by the conducting activity test under fixed conditions.

Modeling of Complex Reforming Reaction of Methane by Response Surface Methodology.

The objective of this study was to investigate the effect of feed composition, space velocity, and reaction temperature on methane/carbon dioxide conversion and H2/CO ratio. Independent variables were feed ratio, flow rate, and reaction temperature while CH4 conversion, CO2 conversion, and H2/CO ratio were set as dependent variables in the complex reaction of methane. As a result of mixed reforming reaction of methane through RSM modeling method, the reaction temperature was found to have the greatest influence. This is because the reaction temperature has the greatest influence on the reaction rate and equilibrium state as a factor directly affecting the thermodynamic value of the catalyst.

Artificial Neural Network for Combined Steam-Carbon Dioxide Reforming of Methane.

The CH4 conversion, CO2 conversion, and H2/CO ratio were set as dependent variables, as the feed rate, flow rate and reaction temperature as independent variables in the complex reaction of methane. We used the Artificial Neural Network (ANN) technique to build a model of the process. The ANN technique was able to predict the reforming process with higher accuracy due to the training capability. The reaction temperature has the greatest effect on the CO2-CH4 reforming reaction. This is because the catalytic reaction temperature has a direct influence on the thermodynamic value and the reaction rate and the equilibrium state.

[Xanthogranulomatous pyelonephritis: clinical, radiological and pathologic characteristics]. / Pielonefritis xantogranulomatosa: características clínicas, radiológicas y anatomo-patológicas.

OBJECTIVES: Xanthogranulomatous pyelonephritis is an atypical chronic infection which simulates a malignant renal neoplasia, definitive diagnosis of which is obtained by pathologic study after surgical removal. In this paper we analyze our experience and compare it to that reported on the literature. METHODS: We performed a retrospective study of cases of xanthogranulomatous pyelonephritis diagnosed in the period from January 1945 to December 2000 at the Institute of Neoplastic Diseases, analyzing clinical, radiological, and surgical features documented in the medical records. RESULTS: There were 11 cases, 82% of them were females. The presence of signs and symptoms such as pain and abdominal mass appeared in 73%, accompanied by hematuria and fever. Most radiological tests showed destruction of the renal parenchyma with abnormalities in the collecting system and obstruction by lithiasis. 91% of the cases had positive urine cultures, being Escherichia coli, Proteus Mirabilis and Klebsiella the most frequent germs. Simple nephrectomy was the surgical treatment, and complications were minimal. CONCLUSIONS: Xanthogranulomatous pyelonephritis should be considered in the differential diagnosis of renal cancer because of its clinical features.