scholarly journals Number density of turbulent vortices in the entire energy spectrum

AIChE Journal ◽  
2014 ◽  
Vol 60 (11) ◽  
pp. 3989-3995 ◽  
Author(s):  
Farideh Ghasempour ◽  
Ronnie Andersson ◽  
Bengt Andersson ◽  
Donald J. Bergstrom
Keyword(s):  
Energy Spectrum ◽  
Number Density ◽  
Entire Energy

scholarly journals Highlights of IAU Symposium No. 167

1995 ◽  
Vol 167 ◽  
pp. 309-313
Author(s):  
Sandro D'Odorico
Keyword(s):  
Energy Spectrum ◽  
Wavelength Range ◽  
Submillimeter Wavelengths ◽  
Array Detectors ◽  
Entire Energy ◽  
Extreme Uv ◽  
Imaging And Spectroscopy ◽  
Visual Range ◽  
Field Imaging

The talks at this IAU Symposium have illustrated the spectacular development which has taken place in the last decade in the field of array detectors for astronomy. Just a few years ago it was possible to speak of two-D detectors for the UV-red wavelength range only. At this meeting we have witnessed presentations on array characteristics from the extreme UV (Bonanno 1995), through the blue-visual range (D'Odorico 1995, Jorden and Oates 1995, Iwert 1995 and Luppino et al. 1995); the infrared 1 to 5 μm window (McLean 1995, Finger et al. 1995, Gilmore et al. 1995, Fazio 1995, Glass et al. 1995 and Ueno et al. 1995); the 10–20 μm window (Fazio 1995, Gezari 1995) and finally to an array of bolometers to operate at submillimeter wavelengths (Moseley 1995). Field imaging and spectroscopy are now possible across this entire energy spectrum and some of the first exciting astronomical results obtained with these devices have been presented here.

Theoretical calculations of pressure-induced shifts of the entire energy spectrum of ruby

1995 ◽  
Vol 7 (25) ◽  
pp. 4883-4893 ◽  
Author(s):  
Ma Dong-Ping ◽  
Liu Yan-Yun ◽  
Wang De-Chao ◽  
Chen Ju-Rong
Keyword(s):  
Energy Spectrum ◽  
Theoretical Calculations ◽  
Entire Energy

Energy Matrix of the d 3 Configuration in Trigonal Field and Analysis of the Entire Energy Spectrum of Ruby

1997 ◽  
Vol 27 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Yan-Yun Liu ◽  
Dong-Ping Ma ◽  
De-Chao Wang ◽  
Ju-Rong Chen
Keyword(s):  
Energy Spectrum ◽  
Energy Matrix ◽  
Entire Energy

Vortex statistics in two-dimensional turbulence based on IB-LBM

2019 ◽  
Vol 33 (36) ◽  
pp. 1950453
Author(s):  
Jianghua Li ◽  
Yuxian Xia ◽  
Xiang Qiu ◽  
Yuehong Qian ◽  
Yulu Liu
Keyword(s):  
Energy Spectrum ◽  
Longitudinal Velocity ◽  
Immersed Boundary ◽  
Grid Turbulence ◽  
Two Dimensional ◽  
Number Density ◽  
Vortex Identification ◽  
Area Formula ◽  
2D Turbulence ◽  
Inverse Cascade

In this paper, the two-dimensional (2D) turbulence perturbed by arrays of cylinders placed both horizontally and vertically is investigated by Immersed Boundary Lattice Boltzmann Method (IB-LBM). The energy spectrum reveals the coexistence of the inverse and direct cascades in 2D grid turbulence. By observing at the distribution of fluxes in space, the energy and enstrophy fluxes have explained the physical mechanism of the double cascades where the two Kolmogorov laws for structure functions are simultaneously observed. The results of vortex statistics by the conditional analysis, which are based on a new and accurate vortex identification criteria called Liutex, show that the algebraic number density [Formula: see text], where [Formula: see text] is vortex area. The time-evolving vortex number density distribution constructs a theoretical framework involving a three-part: [Formula: see text]; [Formula: see text]; [Formula: see text], which is satisfied with the prediction well. The relationship between the vortex circulation [Formula: see text] and vortex area [Formula: see text] is [Formula: see text] and the one between the kinetic energy of vortex [Formula: see text] and [Formula: see text] is [Formula: see text] in the range where [Formula: see text]. Moreover, it has been found that vortices contain about 30% of the total energy of the flow by studying the energy ratio of all vortices to the entire flow field. What is more, it is an interesting phenomenon is that there is only a range where [Formula: see text] in the energy spectrum for the coherent structure field which is obtained by using Liutex as the extraction of vortices. The probability density function (PDF) of the fluctuations of longitudinal velocity shows that an indication of small intermittency in the direct cascade and the absence of intermittency in the inverse cascade range. On the other hand, the scaling exponents [Formula: see text] of the structure function for the inverse cascade are consistent with Kr67 model, which shows the absence of intermittency. While the measured intermittency parameters are [Formula: see text] and [Formula: see text], which explains that there is a very weak intermittent correction in the direct cascade, and ESS has verified the existence of intermittency in our 2D turbulence.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

Energy-filtered imaging of polymer microstructure

1996 ◽  
Vol 54 ◽  
pp. 162-163
Author(s):  
K. Siangchaew ◽  
J. Bentley ◽  
M. Libera
Keyword(s):  
Energy Loss ◽  
Heavy Element ◽  
Spectroscopic Imaging ◽  
Data Set ◽  
Polymer Microstructure ◽  
Entire Energy ◽  
Staining Methods ◽  
Spectrum Imaging ◽  
Resolution Data

Energy-filtered electron-spectroscopic TEM imaging provides a new way to study the microstructure of polymers without heavy-element stains. Since spectroscopic imaging exploits the signal generated directly by the electron-specimen interaction, it can produce richer and higher resolution data than possible with most staining methods. There are basically two ways to collect filtered images (fig. 1). Spectrum imaging uses a focused probe that is digitally rastered across a specimen with an entire energy-loss spectrum collected at each x-y pixel to produce a 3-D data set. Alternatively, filtering schemes such as the Zeiss Omega filter and the Gatan Imaging Filter (GIF) acquire individual 2-D images with electrons of a defined range of energy loss (δE) that typically is 5-20 eV.

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