ExxonMobil

About: ExxonMobil is a company organization based out in Irving, Texas, United States. It is known for research contribution in the topics: Catalysis & Polymerization. The organization has 16969 authors who have published 23758 publications receiving 535713 citations. The organization is also known as: Exxon Mobil Corporation & Exxon Mobil Corp..

Lateral and Upward Soil-Pipeline Interactions in Sand for Deep Embedment Conditions

Abstract: The soil–pipeline interactions in sand under lateral and upward movements are investigated with particular attention to the peak forces exerted on the pipe. The analytical solutions for estimating the peak forces are summarized and it is shown that, for deep embedment condition, there is large uncertainty in the true values since the bounds established by the analytical solutions are large. In order to find the solution for the peak force and to investigate its transition from shallow to deep failure mechanism, finite element analyses of lateral and upward pipe movements are performed for different embedment conditions. Two different soil models (Mohr–Coulomb and Nor–Sand models) are used for the simulations. The accuracy of the analysis is first examined by simulating experimental tank tests. The analysis is further extended to deeper embedment ratios of as large as 100. The obtained finite element results are used to construct a design chart for deep embedded pipelines.

Structural defects in self-assembled organic monolayers via combined atomic beam and x-ray diffraction

Abstract: We present the results of a combined He atom and x‐ray diffraction study of CH3(CH2)n−1SH monolayers self assembled on Au(111) surfaces. By combining these two complementary probes, we have characterized both the surface and the interior structure of the monolayers. In both cases, we find the same structure containing four molecules per unit mesh. However, we demonstrate that there are significant differences in both the diffraction linewidths and the dependence of the linewidth upon chain length for these two techniques.

Homogeneous catalytic hydrogenation. 6. Synthetic and mechanistic aspects of the regioselective reductions of model coal nitrogen, sulfur, and oxygen heteroaromatic compounds using the (.eta.5-pentamethylcyclopentadienyl)rhodium tris(acetonitrile) dication complex as the catalyst precursor

Abstract: The synthetic and mechanistic aspects of the regioselective hydrogenation of representative mono and polynuclear heteroaromatic nitrogen, sulfur, and oxygen model coal compounds such as 2-methylpyridine (1), N-methylindole (2), benzofuran (3), benzothiophene (4), quinoline (5), 2-methylquinoline (6), 5,6- and 7,8-benzoquinolines (7 and 8), and acridine (9) were studied with a (η 5 -pentamethylcuclopentadienyl)rhodium tris(acetonitrile) dicationic complex, [Cp*Rh(CH 3 CN) 3 ] 2+ , as the catalyst precursor. The order of relative rates as a function of structure was found to be 8>>>9>5>7>6>4>>1-3

An approximation for the Xu-White velocity model

Abstract: In 1995, S. Xu and R. E. White described a method for estimating compressional and shear-wave velocities of shaley sandstones from porosity and shale content. Their model was able to predict the effect of increasing clay content on compressional-wave velocity observed in laboratory measurements. A key step in the Xu-White method estimates dry rock bulk and shear moduli for the sand/shale mixture. This step is performed numerically by applying the differential effective medium method to the Kuster-Toksoz equations for ellipsoidal pores. This step is computationally intensive. Using reasonable assumptions about dry rock elastic properties, this step can be replaced with a set of approximations for dry rock bulk and shear moduli. Numerical experiments show an extremely close match between velocities obtained with these approximations and velocities computed with the differential effective medium method. These approximations simplify the application of the Xu-White method, and make the method computationally more efficient. They also provide insight into the Xu-White method. For example, these approximations show how the Xu-White model is related to the critical porosity model.