Planar Top Research Articles

A stratified process for the perception of objects: From optical transformations to 3D relief structure to 3D similarity structure to slant or aspect ratio

Previously, we developed a stratified process for slant perception. First, optical transformations in structure-from-motion (SFM) and stereo were used to derive 3D relief structure (where depth scaling remains arbitrary). Second, with sufficient continuous perspective change (≥45°), a bootstrap process derived 3D similarity structure. Third, the perceived slant was derived. As predicted by theoretical work on SFM, small visual angle (<5°) viewing requires non-coplanar points. Slanted surfaces with small 3D cuboids or tetrahedrons yielded accurate judgment while planar surfaces did not. Normally, object perception entails non-coplanar points. Now, we apply the stratified process to object perception where, after deriving similarity structure, alternative metric properties of the object can be derived (e.g. slant of the top surface or width-to-depth aspect ratio). First, we tested slant judgments of the smooth planar tops of three different polyhedral objects. We tested rectangular, hexagonal, and asymmetric pentagonal surfaces, finding that symmetry was required to determine the direction of slant (AP&P, 2019, https://doi.org/10.3758/s13414-019-01859-5). Our current results replicated the previous findings. Second, we tested judgments of aspect ratios, finding accurate performance only for symmetric objects. Results from this study suggest that, first, trackable non-coplanar points can be attained in the form of 3D objects. Second, symmetry is necessary to constrain slant and aspect ratio perception. Finally, deriving 3D similarity structure precedes estimating object properties, such as slant or aspect ratio. Together, evidence presented here supports the stratified bootstrap process for 3D object perception. Statement of significancePlanning interactions with objects in the surrounding environment entails the perception of 3D shape and slant. Studying ways through which 3D metric shape and slant can be perceived accurately by moving observers not only sheds light on how the visual system works, but also provides understanding that can be applied to other fields, like machine vision or remote sensing. The current study is a logical extension of previous studies by the same authors and explores the roles of large continuous perspective changes, relief structure, and symmetry in a stratified process for object perception.

The reticulate coral reef system in Golfo de Guacanayabo, SE Cuba

The Gran Banco de Buena Esperanza (GBBE) coral reef system in Golfo de Guacanayabo in southeastern Cuba consists of a reticular structure comprising a maze of steep to vertical ridges with planar tops rising 20–25 m from the bay floor. The planar tops of the ridges are densely populated by small colonies of sediment-resistant Scleractinia with fragile, branching colony growth forms. The initiation of a reticulate reef system in the absence of karst or other antecedent hard substrates is unprecedented. In this note, we describe the unique geological setting, geomorphology and scleractinian diversity of the GBBE and present an explanation for its development. We suggest that convection-driven self-organization of coral skeletal fragments may be responsible for the reticulate pattern observed as 75 m of reef limestone accreted during Holocene time. Finally, we briefly discuss the evolutionary benefits of coral hybridization and the potential for rapid coral reef growth in turbid, muddy environments.

Rotational Friction and Diffusion of Quantum Rotors.

We present the Markovian quantum master equation describing rotational decoherence, friction, diffusion, and thermalization of planar, linear, and asymmetric rotors in contact with a thermal environment. It describes how an arbitrary initial rotation state decoheres and evolves toward a Gibbs-like thermal ensemble, as we illustrate numerically for the linear and the planar top, and it yields the expected rotational Fokker-Planck equation of Brownian motion in the semiclassical limit.

On Separation of the Torsional and Rotational Motions in a Molecule with Two Identical Planar Tops. The Allene Molecule

On Separation of the Torsional and Rotational Motions in a Molecule with Two Identical Planar Tops. The Allene Molecule

On Separation of Torsional and Rotational Motions in a Molecule with Two Identical Planar Tops. The Ethylene Molecule

A procedure for separating the torsional and rotational motions in molecules with two identical planar tops on a linear core is considered for the example of the ethylene molecule C2H4 in the ground electronic state.

Crossbar architecture for tera-scale integration

As far as the fabrication of ultradense crossbars is related to correspondingly dense wire arrays, the crossbar route to tera-scale integration depends on the availability of preparation techniques for wire arrays with density of 106 cm−1 or more. For a planar arrangement this density implies a pitch of 10 nm or less, beyond the current possibility and close to the theoretical limit, assuming for the cross-point a minimum area of 10 nm2. Further increase of density can only be achieved organizing the nanowires in a three-dimensional fashion. This paper describes a planar top–down process for the preparation of vertically arranged poly-silicon nanowires. The technique is expected to allow the production of wire arrays with linear density (projected on the surface) larger than those achievable with any other proposed top–down processes. Used for the fabrication of the bottom wire array of crossbars, this process should allow an eventual cross-point density of the order of 1012 cm−2, thus being a candidate technology for tera-scale integration.

Anisotropy of ensembles of free polyatomic photoisomers

In order to describe the polarization response of an ensemble of molecules undergoing structural transformations (photoisomerization) under collisionless conditions, we have calculated the orientational correlation functions. We assume that changes in molecular structure can be considered as instantaneous on the molecular rotation scale. We have obtained general expressions for the anisotropy when the original molecule and the photoisomer are asymmetric tops. We have performed anisotropy calculations for steady-state experimental conditions and a number of limiting situations, when the characteristic times of the photoreaction are much shorter or much longer than the molecular reorientation times and when the original molecule and the photoisomer are planar tops. We have shown that detecting the polarization response allows us to estimate the characteristic times of the photoreaction and to determine the intramolecular orientation of the transition dipole moments for transitions with absorption and emission of light.

Rayleigh–Bénard instability in a vertical cylinder with a rotating magnetic field

This paper presents a linear stability analysis for the Rayleigh–Bénard convection in a finite-length, vertical cylinder with a rotating magnetic field. The vertical wall of the cylinder is adiabatic, and the planar top and bottom walls are isothermal with a higher temperature at the bottom. The stabilizing effects of the rotating magnetic field are studied for four values of the Prandtl number. Results for one Prandtl number are compared to previously published experimental results.

Formation and mechanism of the abnormal pressure zone and its relation to oil and gas accumulations in the Eastern Jiuquan Basin, northwest China

Three abnormal overpressure zoes with a planar top at different depths occur in the Ying'er Depression in the Eastern Jiuquan Basin. The distance and the temperature difference between them are about 1 000 m and 30℃, respectively. The studies of sedimentary history, nature of formation water, variation of geothermal gradient and examination of thin sections, and the relationship between lithologic section and formation pressure show that there are conditions for formation of abnormal overpressure zones in the Ying'er Depression. Aquathermal pressuring and the overlying sediment load are main factors forming the abnormal overpressure zones. The study indicates that most of oil and gas in the Ying'er Depression accumulated in reservoirs above or under the seals or in the top of the compartments.

Generation and Migration of Petroleum from Abnormally Pressured Fluid Compartments (1)

Much of the world's oil and gas has been generated from source rocks inside deep (> 3,000 m or 9,840 ft) seal-bounded fluid compartments. The quantity and composition of the kerogen and the burial history of the source rocks determine the volumes of petroleum generated; however, the migration from the compartments in an oil and gas phase is a pressure-driven process in which the flow direction is controlled by the configuration and internal pressures of the fluid compartments. Many sedimentary basins contain layers of two or more superimposed hydrogeological systems. The shallow systems are usually basin wide in extent and exhibit normal hydrostatic pressures. The deeper systems, where the oil is generated, are not basin wide and are abnormally over pressured. They usu lly consist of a series of individual fluid compartments that are not in hydraulic pressure communication with each other nor with the overlying hydrodynamic regime. Tops of fluid compartments in currently sinking basins do not always follow a specific stratigraphic horizon. They frequently have planar tops and subsurface temperatures ranging from 90 degrees to 100 degrees C (194 degrees to 212 degrees F). The tops in clastic sediments appear to be caused by carbonate mineralization along a thermocline. In the North Sea, the depth to the top of the deepest seal changes with the geothermal gradient. The seal is deeper where the gradient is lower. The generation of oil and gas within the compartments plus the thermal expansion of pore fluids eventually causes fracturing of the top compartment seal during periods of basin sinking. Hydrocarbons and other pore fluids then move vertically into the overlying lower pressured sediments and accumulate in the nearest structural and stratigraphic traps. Seal fracturing causes a pressure drop with compartment fluids rushing to the breakout point. The compartment then re-seals and pressure builds to another breakout. This episodic process continues with resealing and breakout cycles probably occurring in intervals of thousands of years in rapidly sinking basins such as the United States Gulf Coast. This concept of episodic dewatering of deep-basin fluid compartments needs to be considered n any basin-modeling program where the bulk of the oil generation occurs in the compartmented overpressured section of the basin and the oil moves vertically into the normally pressured rocks above.

Products and Processes of Ancient Arid Coastline: Lower Cutler Group (Permian), Southeastern Utah: ABSTRACT

End_Page 950------------------------------In Canyonlands National Park, the Ceder Mesa Sandstone consists of 700 ft (213 m) of large-scale trough, cross-bedded, well-sorted sandstone. It conformably overlies 1,100 ft (335 m) of interbedded sandstone, limestone, and shale of the Elephant Canyon Formation. Sandstones of both formations, formerly interpreted as shallow marine, are here interpreted as eolian due to occurrence of: (1) subcritically climbing translatent strata produced by migrating wind ripples; (2) unimodal southeasterly dips; (3) rare vertebrate fossils and trackways; (4) gypsum sand crystal pseudomorphs; and (5) abundant calcified plant roots. In contrast, limestones, conglomeratic sandstones, and shales of the Elephant Canyon contain diverse marine body and trace fossil faunas, and dip directions are widely dis ersed. Roots occur along twelve major bedding planes in the Cedar Mesa, several of which can be traced at least 16 mi (26 km). These planes are not channeled by overlying trough cross-beds. Planes do not climb downwind and are thus unrelated to migrating bedforms. Roots also occur along the planar tops of 15 eolian sandstone bodies in the Elephant Canyon, but are there overlain by fossiliferous marine carbonates. The planes are interpreted as eolian deflation surfaces resulting from decreased sand supply to a coastal dune field. A modern analogy is the Sabkha Matti south of the Persian gulf. Colonization by plants and growth of gypsum sand crystals was followed by transgression (Elephant Canyon) or by renewal of erg conditions (Cedar Mesa). Eustatic control of both sand supply and deflation s a strong possibility. End_of_Article - Last_Page 951------------

Selection Rules for Rotor Transitions in Completely Asymmetric Molecules with Planar Top and Frame and a Twofold Barrier

Abstract In this contribution selection rules for rotation torsion transitions are considered for completely asymmetric molecules. Quade gave two descriptions of this type of molecules resulting in two different invariance groups of both Hamiltonians lead to indentical selection rules.