Shallow Ocean Bottom BRDF Prediction, Modeling, and Inversion Via Simulation With Surface/Volume Data Derived From X-Ray Tomography

AbstractDelindeite and lourenswalsite are two new barium titanosilicate minerals found as microscopic crystals in miarolitic cavities in nepheline syenite in the Diamond Jo quarry, Hot Spring County, Arkansas. Delindeite is found as aggregates of flake-like crystallites in compact spherules, light pinkish grey in colour, with a resinous, pearly lustre. The flakes are biaxial positive with average n ∼ 1.813; the measured density is 3.3 g/cm3. Electron diffraction revealed a monoclinic unit cell in space group C2/m or subgroup, with a = 21.617(13), b = 6.816(5), c = 5.383(3) Å, β = 94.03(5)° (refined from X-ray powder data). The strongest X-ray lines are (hkl, dobs, Irel): (200, 10.80, 100); (311, 3.54, 24); (6̄01, 3.083, 28); (601, 2.888, 31); (2̄21, 2.806, 20); (910, 2.262,18). The crystals are submicroscopically twinned on (100) and also produce additional continuous diffraction streaks parallel to a*, which double the b and c axes. The formula derived from electron and ion probe analyses (H2O by difference), as constrained by density and molar volume data, is approximately (Na,K)2.7(Ba,Ca)4(Ti,Fe,Al)6Si8O26(OH)14, with Na > K, Ba ≫ Ca, Ti ≫ Fe,Al; Z = 1. Lourenswalsite occurs as very thin hexagonal plates in rosettes, silver grey to light brownish grey in colour. The crystals are biaxial negative with very low 2V angle. Indices of refraction are nα = 1.815, nβ ≈ nγ = 1.840; the measured density is 3.17 g/cm = 1.840; the measured density is 3.17 g/cm3. X-ray and electron diffraction show a sharp pseudohexagonal lattice with a = 5.244 Å, but extremely diffuse diffraction streaks normal to the hk0 plane. In these streaks a period of 20.5 Å can be discerned. A hexagonal unit cell with a = 5.244(2) Å, c = 20.49(3) Å can be refined from the powder diffraction data but does not account for some lines, probably because of extreme layer disorder as shown by precession single-crystal patterns. The strong X-ray powder lines are (002, 10.22, 20); (-, 3.93, 20); (111, 2.608, 100); (300, 1.5145, 80); (220, 1.3111, 25). The formula given by microprobe analyses, constrained by density and molar volume data, is approximately (K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12 with K > Ba, Ti ≫ (Mg,Ca,Fe), Si > Al > Fe; Z = 1. These minerals are formed under oxidizing weathering conditions, and iron is assumed to be in the Fe3+ state.

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Mimetic finite-difference coupled-domain solver for anisotropic media

Geophysics ◽

10.1190/geo2020-0092.1 ◽

2021 ◽

Vol 86 (1) ◽

pp. T45-T59

Author(s):

Harpreet Sethi ◽

Jeffrey Shragge ◽

Ilya Tsvankin

Keyword(s):

Finite Difference ◽

Boundary Conditions ◽

Model Building ◽

Fluid Layer ◽

Anisotropic Media ◽

Horizontal Displacement ◽

Solid Boundary ◽

Ocean Bottom ◽

Solid Interface ◽

And Inversion

Accurately modeling full-wavefield solutions at and near the seafloor is challenging for conventional single-domain elastic finite-difference (FD) methods. Because they treat the fluid layer as a solid with zero shear-wave velocity, the energy partitioning for body and surface waves at the seafloor is distorted. This results in incorrect fluid/solid boundary conditions, which has significant implications for imaging and inversion applications that use amplitude information for model building. To address these issues, here we use mimetic FD (MFD) operators to develop and test a numerical approach for accurately implementing the boundary conditions at a fluid/solid interface. Instead of employing a single “global” model domain, we partition the full grid into two subdomains that represent the acoustic and elastic (possibly anisotropic) media. A novel split-node approach based on one-sided MFD operators is introduced to distribute grid points at the fluid/solid interface and satisfy the wave equation and the boundary conditions. Numerical examples demonstrate that such MFD operators achieve stable implementation of the boundary conditions with the same (fourth) order of spatial accuracy as that inside the split-domain interiors. We compare the wavefields produced by the MFD scheme with those from a more computationally expensive spectral-element method to validate our algorithm. The modeling results help analyze the events associated with the fluid/solid (seafloor) interface and provide valuable insights into the horizontal displacement or velocity components (e.g., recorded in ocean-bottom-node data sets). The developed MFD approach can be efficiently used in elastic anisotropic imaging and inversion applications involving ocean-bottom seismic data.

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Lewis-Base Adducts of Group 11 Metal(I) Compounds. LIII. Synthesis and Structural Characterization of Binuclear μ,μ'-Dichloro-, Dibromo and Diiodo-bis[(pyridine)(triphenylphosphine)copper(I)] Complexes, and Their Pyridine-4-carbonitrile Analogues

Australian Journal of Chemistry ◽

10.1071/ch9890913 ◽

1989 ◽

Vol 42 (6) ◽

pp. 913 ◽

Cited By ~ 26

Author(s):

LM Engelhardt ◽

PC Healy ◽

JD Kildea ◽

AH White

Keyword(s):

Single Crystal ◽

Structural Characterization ◽

Lewis Base ◽

The Other ◽

X Ray ◽

Structure Determinations ◽

M Phase ◽

And Inversion ◽

Iodide Single Crystal

Mixed base pyridine (py)/triphenylphosphine adducts of the copper(1) halides, CuX, have been synthesized for 1 : 1 : 1 stoichiometry for X = chloride and iodide; single-crystal X-ray structure determinations of these show them to be isomorphous and isostructural with that of the bromide recorded elsewhere, being �,�′- dihalo-bridged dimers , [(PPh3)( py )CuX2Cu( py )(PPh3)], monoclinic, C2/c, a ≈ 26.2, b ≈ 14.3, c ≈ 11 .2 � , β ≈ 95, Z = 4 dimers. The bromide has been isolated as a new monoclinic C 2/m polymorph, a 11 .279(8), b 14.268(6), c 13.858(4) �, β 109.33(6)�, Z=4 dimers, and details of its structure are also recorded. The structures of their pyridine-4-carbonitrile (pycn) analogues have also been determined and found to be also binuclear, with no cyano-copper interactions; these also are an isomorphous, isostructural series, monoclinic P21/n, a ≈ 15.4, b ≈ 8.1, c ≈ 17.9 � , β ≈ 101 �, Z = 2 dimers. In each series of dimers, one half of the dimer is crystallographically independent, the generators of the other half being twofold rotor (C2/c phase), mirror (C2/m phase) and inversion centre (P21/n phase) respectively.

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X-ray micro-tomographic data of live larvae of the beetle Cacosceles newmannii

10.31730/osf.io/2urxf ◽

2021 ◽

Author(s):

Philipp Lehmann ◽

Marion Javal ◽

Anton du Plessis ◽

Muofhe Tshibalanganda ◽

John S. Terblanche

Keyword(s):

Image Segmentation ◽

3D Models ◽

Volumetric Data ◽

Volume Data ◽

X Ray ◽

Segmentation Methods ◽

Body Sizes ◽

Tomographic Data ◽

Micro Tomography

Quantifying insect respiratory structures and their variation has remained challenging due to their microscopic size. Here we measure insect tracheal volume using X-ray micro-tomography (µCT) scanning (at 15 µm resolution) on living, sedated larvae of the cerambycid beetle Cacosceles newmannii across a range of body sizes. In this paper we provide the full volumetric data and 3D models for 12 scans, providing novel data on repeatability of imaging analyses and structural tracheal trait differences provided by different image segmentation methods. The volume data is provided here with segmented tracheal regions as 3D models.

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The numerical synthesis and inversion of acoustic fields using the Hankel transform with application to the estimation of the plane wave reflection coefficient of the ocean bottom

10.1575/1912/2590 ◽

1983 ◽

Cited By ~ 2

Author(s):

Douglas Robert Mook

Keyword(s):

Reflection Coefficient ◽

Plane Wave ◽

Wave Reflection ◽

Hankel Transform ◽

Ocean Bottom ◽

Acoustic Fields ◽

And Inversion ◽

Numerical Synthesis

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Development of Metrological NDE Methods for Microturbine Ceramic Components

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education ◽

10.1115/2000-gt-0639 ◽

2000 ◽

Author(s):

H.-R. Lee ◽

W. A. Ellingson

Keyword(s):

Data Acquisition ◽

Vertical Plane ◽

Coordinate Measuring Machine ◽

Image Intensifier ◽

Reconstruction Algorithms ◽

Volume Data ◽

X Ray ◽

Computed Tomographic ◽

X Ray Computed ◽

Measuring Machine

In this work, X-ray computed tomographic imaging technology with high spatial resolution has been explored for metrological applications to Si3N4 ceramic turbine wheels. X-ray computed tomography (XCT) data were acquired by a charge-coupled device detector coupled to an image intensifier. Cone-beam XCT reconstruction algorithms were used to allow full-volume data acquisition from the turbine wheels. Special software was developed so that edge detection and complex blade contours could be determined from the XCT data. The feasibility of using the XCT for dimensional analyses was compared with that of a coordinate-measuring machine (CMM). Details of the XCT system, data acquisition, and dimensional comparisons will be presented. Comparison between XCT and CMM dimensions shows that the 3D XCT data have an accuracy of ± 0.2 mm in all three axis whereas the CMM data have an accuracy of ± 0.5 mm in the horizontal plane and ± 0.025 mm in the vertical plane.

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X-ray micro-tomographic data of live larvae of the beetle Cacosceles newmannii

Gigabyte ◽

10.46471/gigabyte.18 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Philipp Lehmann ◽

Marion Javal ◽

Anton Du Plessis ◽

Muofhe Tshibalanganda ◽

John S. Terblanche

Keyword(s):

Image Segmentation ◽

3D Models ◽

Volumetric Data ◽

Volume Data ◽

X Ray ◽

Segmentation Methods ◽

Body Sizes ◽

Tomographic Data ◽

Micro Tomography

Quantifying insect respiratory structures and their variation has remained challenging due to their microscopic size. Here we measure insect tracheal volume using X-ray micro-tomography (μCT) scanning (at 15 μm resolution) on living, sedated larvae of the cerambycid beetle Cacosceles newmannii across a range of body sizes. In this paper we provide the full volumetric data and 3D models for 12 scans, providing novel data on repeatability of imaging analyses and structural tracheal trait differences provided by different image segmentation methods. The volume data is provided here with segmented tracheal regions as 3D models.

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Structural Study of δ-AlOOH Up to 29 GPa

Minerals ◽

10.3390/min10121055 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1055

Author(s):

Dariia Simonova ◽

Elena Bykova ◽

Maxim Bykov ◽

Takaaki Kawazoe ◽

Arkadiy Simonov ◽

...

Keyword(s):

Phase Transition ◽

Synchrotron Radiation ◽

Equation Of State ◽

Room Temperature ◽

Diamond Anvil Cell ◽

Volume Data ◽

X Ray Diffraction ◽

X Ray ◽

Diamond Anvil ◽

Murnaghan Equation

A structure and equation of the state of δ-AlOOH has been studied at room temperature, up to 29.35 GPa, by means of single crystal X-ray diffraction in a diamond anvil cell using synchrotron radiation. Above ~10 GPa, we observed a phase transition with symmetry changes from P21nm to Pnnm. Pressure-volume data were fitted with the second order Birch-Murnaghan equation of state and showed that, at the phase transition, the bulk modulus (K0) of the calculated wrt 0 pressure increases from 142(5) to 216(5) GPa.

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