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Technical Paper

A New Method for Characterization of Porous Structure without Mercury; Application to Porous Materials of Diesel Particulate Filters

2013-04-08
2013-01-0457
Mercury porosimetry (MP) is one of the analytical methods to measure the porosity and the pore size distribution of porous materials. We have developed a new method of digital mercury porosimetry (DMP) for characterizing the porous structure by simulating the measuring processes of MP without using any mercury. Firstly, the contact angle between the mercury and the substance surfaces is theoretically calculated by quantum chemical molecular dynamics. Secondly, a group of images showing the porous structure is obtained with an X-ray computed tomography scanner, and then a three-dimensional digital model is reconstructed connecting the pores/substances boundaries between each image. Thirdly, mercury intrusion which is a fundamental process of the MP method is digitally simulated. The digital mercury intrudes into pores of the digital model from its circumference with the theoretically calculated contact angle.
Journal Article

Multi-scale Theoretical Study of Sintering Dynamics of Pt for Automotive Catalyst

2009-11-02
2009-01-2821
The capability of theoretical durability studies to offer an efficient alternative methodology for predicting the potential performance of catalysts has improved in recent years. In this regard, multi-scale theoretical methods for predicting sintering behavior of Pt on various catalyst supports are being developed. Various types of Pt diffusions depending on support were confirmed by the micro-scale ultra accelerated quantum chemical molecular dynamics (UA-QCMD) method. Moreover, macro-scale sintering behavior of Pt/ɣ-Al2O3, Pt/ZrO2 and Pt/CeO2 catalyst were studied using a developed 3D sintering simulator. Experimental results were well reproduced. While Pt on ɣ-Al2O3 sintered significantly, Pt on ZrO2 sintered slightly and Pt on CeO2 demonstrated the highest stability against sintering.
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