Mobil

About: Mobil is a based out in . It is known for research contribution in the topics: Catalysis & Zeolite. The organization has 7085 authors who have published 10642 publications receiving 237497 citations. The organization is also known as: Socony-Vacuum Oil Company & Standard Oil Company of New York.

Structure of synthetic zeolite ZSM-5

Abstract: ZEOLITE ZSM-5 (ref. 1) is a member of a new class of shape selective catalysts with unique channel structures which differ from the familiar large-pore faujasite and small-pore zeolites such as Linde Type A and erionite. They also possess unusual catalytic properties and have high thermal stability. We have determined their structure using model building, single crystal and powder X-ray data.

MCM-22: A Molecular Sieve with Two Independent Multidimensional Channel Systems

Abstract: The molecular sieve MCM-22 contains structural features previously unobserved in this class of materials. Its framework topology, derived from high-resolution electron micrographs and refined with synchrotron x-ray diffraction powder data, contains two independent pore systems, both of which are accessed through rings composed of ten tetrahedral (T) atoms (such as Si, Al, and B). One of these pore systems is defined by two-dimensional, sinusoidal channels. The other consists of large supercages whose inner free diameter, 7.1 angstroms, is defined by 12 T-O species (12-rings) and whose inner height is 18.2 angstroms. These coexisting pore systems may provide opportunities for a wide variety of catalytic applications in the petrochemical and refining industries. Another structural feature is an unusual -T-O-T- chain that passes through the center of a modified dodecasil-1H [4(3)5(6)6(3)] cage.

Alluvial Fans and their Natural Distinction from Rivers Based on Morphology, Hydraulic Processes, Sedimentary Processes, and Facies Assemblages

Abstract: Contrary to common contemporary usage, alluvial fans are a naturally unique phenomenon readily distinguishable from other sedimentary environments, including gravel-bed rivers, on the basis of morphology, hydraulic processes, sedimentologic processes, and facies assemblages. The piedmont setting of alluvial fans where the feeder channel of an upland drainage basin intersects the mountain front assures that catastrophic fluid gravity flows and sediment gravity flows, including sheetfloods, rock falls, rock slides, rock avalanches, and debris flows, are major constructional processes, regardless of climate. The unconfinement of these flows at the mountain front gives rise to the high-sloping, semiconical form that typifies fans. The plano-convex cross-profile geometry inherent in this f rm is the inverse of the troughlike cross-sectional form of river systems, and precludes the development of floodplains that characterize rivers. The relatively high slope of alluvial fans creates unique hydraulic conditions where passing fluid gravity flows attain high capacity, high competency, and upper flow regime, resulting in sheetfloods that deposit low-angle antidune or surface-parallel planar-stratified sequences. These waterlaid facies contrast with the typically lower-flow-regime thick-bedded, cross-bedded, and lenticular channel facies, and associated floodplain sequences, of rivers. The unconfinement of flows on fans causes a swift decrease in velocity, competency, and capacity as they attenuate, inducing rapid deposition that leads to the angular, poorly sorted textures and short radii typical of fans. This condition is markedly different than for rivers, where sediment gravity flows are rare and water flows remain confined by channel walls or spill into floodplains, and increase in depth downstream. The distinctive processes that construct alluvial fans, coupled with the secondary surficial reworking of their deposits, yield unique facies assemblages that permit the easy differentiation of fan sequences even where the geomorphic context has been lost, including in the rock record. The fault-proximal piedmont setting critical for their preservation makes properly identified alluvial-fan deposits in the rock record an invaluable tool for reconstructing and interpreting the tectonic and stratigraphic evolution of ancient sedimentary basins and their contained register of Earth history.