scholarly journals Characterization of the planetary nebula Tc 1 based on VLT X-shooter observations

2019 ◽  
Vol 490 (2) ◽  
pp. 2475-2494 ◽  
Author(s):  
Isabel Aleman ◽  
Marcelo L Leal-Ferreira ◽  
Jan Cami ◽  
Stavros Akras ◽  
Bram Ochsendorf ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Three Dimensional ◽  
Central Star ◽  
Gas Temperature ◽  
Spatially Resolved ◽  
Morphological Model ◽  
Density Enhancement ◽  
First Time ◽  
The Empirical Analysis

ABSTRACT We present a detailed analysis of deep VLT/X-Shooter observations of the planetary nebula Tc 1. We calculate gas temperature, density, extinction, and abundances for several species from the empirical analysis of the total line fluxes. In addition, a spatially resolved analysis of the most intense lines provides the distribution of such quantities across the nebula. The new data reveal that several lines exhibit a double peak spectral profile consistent with the blue and redshifted components of an expanding spherical shell. The study of such components allowed us to construct for the first time a three-dimensional morphological model, which reveals that Tc 1 is a slightly elongated spheroid with an equatorial density enhancement seen almost pole on. A few bright lines present extended wings (with velocities up to a few hundred km s−1), but the mechanism producing them is not clear. We constructed photoionization models for the main shell of Tc 1. The models predict the central star temperature and luminosity, as well as the nebular density and abundances similar to previous studies. Our models indicate that Tc 1 is located at a distance of approximately 2 kpc. We report the first detection of the [Kr iii] 6825 Å emission line, from which we determine the Krypton abundance. Our model indicates that the main shell of Tc 1 is matter bounded; leaking H ionizing photons may explain the ionization of its faint AGB-remnant halo.

scholarly journals Mapping the physical and chemical properties of the planetary nebula NGC 3242

2011 ◽  
Vol 7 (S283) ◽  
pp. 448-449
Author(s):  
Hektor Monteiro ◽  
Denise Gonçalves ◽  
Marcelo Leal-Ferreira ◽  
Romano Corradi ◽  
Sebastian Sánchez
Keyword(s):  
Planetary Nebula ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Small Scale ◽  
Chemical Abundances ◽  
Electronic Density ◽  
Spatially Resolved ◽  
Integral Field Spectroscopy ◽  
Main Components ◽  
Physical And Chemical

AbstractWe present optical integral field spectroscopy analysis of the main components, with the exception of the halo, as well as of the detected small-scale structures of the planetary nebulae NGC 3242. The observations were obtained with the VIMOS instrument attached to VLT-UT3. Spatially resolved maps of the electronic density (Ne), temperatures (Te) and chemical abundances, i.e., in a pixel to pixel fashion of the small and large-scales structures of this planetary nebula are determined in this work. These diagnostic and abundance maps represent important constraints for future detailed three dimensional photoionization modeling of the nebula, as well as providing important information on biases introduced by traditional slit observations.

DISPERSIVE FRACTAL CHARACTERIZATION OF KIDNEY ARTERIES BY THREE-DIMENSIONAL MASS-RADIUS-ANALYSIS

Fractals ◽  
1995 ◽  
Vol 03 (04) ◽  
pp. 879-891 ◽  
Author(s):  
M. SERNETZ ◽  
M. JUSTEN ◽  
F. JESTCZEMSKI
Keyword(s):  
Fractal Structure ◽  
Three Dimensional ◽  
Arterial System ◽  
Data Sets ◽  
Scaling Properties ◽  
Local Scaling ◽  
Living Organisms ◽  
Global And Local ◽  
First Time

Three-dimensional data sets of kidney arterial vessels were obtained from resin casts by serial sectioning and by micro-NMR-tomography, and were analyzed by the mass-radius-relation both for global and local scaling properties. We present for the first time the spatial resolution of local scaling and thus the dispersion of the fractal dimension within the organs. The arterial system is characterized as a non-homogeneous fractal. We discuss and relate the fractal structure to the scaling and allometry of metabolic rates in living organisms.

scholarly journals Numerical Characterization of the Performance of Fluid Pumps Based on a Wankel Geometry

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Stephen Wan ◽  
Jason Leong ◽  
Te Ba ◽  
Arthur Lim ◽  
Chang Wei Kang
Keyword(s):  
Three Dimensional ◽  
Mechanical Efficiency ◽  
Planar Geometry ◽  
Pump Efficiency ◽  
Capacity Coefficient ◽  
Numerical Characterization ◽  
Pump Flow Rate ◽  
Low Efficiency ◽  
First Time

The performance of fluid pumps based on Wankel-type geometry, taking the shape of a double-lobed limaçon, is characterized. To the authors’ knowledge, this is the first time such an attempt has been made. To this end, numerous simulations for three different pump sizes were carried out and the results were understood in terms of the usual scaling coefficients. The results show that such pumps operate as low efficiency (<30%) valveless positive displacements pumps, with pump flow-rate noticeably falling at the onset of internal leakage. Also, for such pumps, the mechanical efficiency varies linearly with the head coefficient, and, within the onset of internal leakage, the capacity coefficient holds steady even across pump efficiency. Simulation of the flow field reveals a structure rich in three-dimensional vortices even in the laminar regime, including Taylor-like counterrotating vortex pairs, pointing towards the utility of these pumps in microfluidic applications. Given the planar geometry of such pumps, their applications as microreactors and micromixers are recommended.

scholarly journals Planetary nebulae with Wolf-Rayet-type central stars - II. Dissecting the compact planetary nebula M 2-31 with GTC MEGARA

2021 ◽  
Author(s):  
J S Rechy-García ◽  
J A Toalá ◽  
S Cazzoli ◽  
M A Guerrero ◽  
L Sabin ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Spectral Properties ◽  
Narrow Band ◽  
Central Star ◽  
Comprehensive Analysis ◽  
High Dispersion ◽  
Medium Resolution ◽  
First Time ◽  
Integral Field ◽  
Central Stars

Abstract We present a comprehensive analysis of the compact planetary nebula M 2-31 investigating its spectral properties, spatio-kinematical structure and chemical composition using GTC MEGARA integral field spectroscopic observations and NOT ALFOSC medium-resolution spectra and narrow-band images. The GTC MEGARA high-dispersion observations have remarkable tomographic capabilities, producing an unprecedented view of the morphology and kinematics of M 2-31 that discloses a fast spectroscopic bipolar outflow along position angles 50○ and 230○, an extended shell and a toroidal structure or waist surrounding the central star perpendicularly aligned with the fast outflows. These observations also show that the C ii emission is confined in the central region and enclosed by the [N ii] emission. This is the first time that the spatial segregation revealed by a 2D map of the C ii line implies the presence of multiple plasma components. The deep NOT ALFOSC observations allowed us to detect broad WR features from the central star of M 2-31, including previously undetected broad O vi lines that suggest a reclassification as a [WO4]-type star.

A study of the mineralization of bone by high voltage EM tomography

1992 ◽  
Vol 50 (1) ◽  
pp. 582-583
Author(s):  
James Arena ◽  
Bruce F. McEwen ◽  
Min Ja Song ◽  
William J. Landis
Keyword(s):  
High Voltage ◽  
Three Dimensional ◽  
Structural Features ◽  
Complete Characterization ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Vertebrate Model ◽  
Em Tomography ◽  
First Time

Complete characterization of the inorganic and organic interaction in calcifying tissues is fundamental to understanding their structure-function relations. In this context, high resolution tomographic three-dimensional (3D) reconstruction of normally calcifying avian tendon imaged by high voltage electron microscopy has recently been used to determine specific structural features of hydroxyapatite crystals associated with collagen fibrils in this vertebrate model of biological mineralization. The present work is an extension of these previous investigations, now applied to bone for the first time.

scholarly journals Fabrication, Experiments, and Analysis of an LBM Additive-Manufactured Flexure Parallel Mechanism

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 572 ◽  
Author(s):  
Huaxian Wei ◽  
Li Wang ◽  
Xiaodong Niu ◽  
Jian Zhang ◽  
Alessandro Simeone
Keyword(s):  
Additive Manufacturing ◽  
Parallel Mechanism ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Element Analysis ◽  
Flexure Mechanism ◽  
Laser Beam Melting ◽  
Stiffness Characteristics ◽  
First Time

Additive manufacturing technology has advantages for realizing complex monolithic structures, providing huge potential for developing advanced flexure mechanisms for precision manipulation. However, the characteristics of flexure hinges fabricated by laser beam melting (LBM) additive manufacturing (AM) are currently little known. In this paper, the fabrication and characterization of a flexure parallel mechanism through the LBM process are reported for the first time to demonstrate the development of this technique. The geometrical accuracy of the additive-manufactured flexure mechanism was evaluated by three-dimensional scanning. The stiffness characteristics of the flexure mechanism were investigated through finite element analysis and experimental tests. The effective hinge thickness was determined based on the parameters study of the flexure parallel mechanism. The presented results highlight the promising outlook of LBM flexure parts for developing novel nanomanipulation platforms, while additional attention is required for material properties and manufacturing errors.

Organic–inorganic hybrid three-dimensional metal sulfite-oxalates with honeycomb-like structures

2017 ◽  
Vol 46 (18) ◽  
pp. 5911-5917 ◽  
Author(s):  
Ranjay K. Tiwari ◽  
J. N. Behera
Keyword(s):  
Three Dimensional ◽  
Hydrothermal Conditions ◽  
Inorganic Hybrid ◽  
Mixed Metal ◽  
First Time

The crystallographic signatures and characterization of two novel mixed metal hybrid open-frameworks [Na2Mn2(C2O4)(SO3)2(H2O)2], 1 and [NaEu(C2O4)(SO3)(H2O)3], 2 are reported for the first time; they are synthesized under hydrothermal conditions to generate 3D assemblies and honeycomb-like structures.

scholarly journals A possible stellar interaction with NGC 246

1997 ◽  
Vol 180 ◽  
pp. 264-264
Author(s):  
Grant J. Miller
Keyword(s):  
Planetary Nebula ◽  
Morphological Feature ◽  
Central Star ◽  
Line Of Sight ◽  
Homogeneous Distribution ◽  
Program Star ◽  
High Degree ◽  
First Time

The planetary nebula NGC 246 has a high degree of symmetry about its central star, and can be described most graphically as a filled disk. Direct images of NGC 246 reveal a relatively homogeneous distribution of gases, with an unusual morphological feature that appears to contain less of the nebular material. At the center of this roughly circular feature, in the southeast quadrant of the nebula, there is a star (hereafter referred to as “the program star”). The placement of the program star is very suggestive of a wind blown cavity in the PN. The question of whether this star actually is interacting with the nebula, or merely along the line-of-sight, is addressed here for the first time.

The dramatic kinematics of the hydrogen deficient Planetary Nebula Abell 30

1997 ◽  
Vol 180 ◽  
pp. 261-261
Author(s):  
J. Meaburn ◽  
J. A. López
Keyword(s):  
Planetary Nebula ◽  
Velocity Structure ◽  
Spatially Resolved ◽  
San Pedro ◽  
First Time ◽  
Echelle Spectrometer

The remarkable velocity structure of the different components of the hydrogen deficient planetary nebula Abell 30 have been revealed for the first time by obtaining spatially resolved profiles of the [O III] 5007 å lines with the Manchester echelle spectrometer combined with the 2.1 m San Pedro Mártir telescope.

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