scholarly journals A new method for measuring optical scattering properties of atmospherically relevant dusts using the Cloud Aerosol Spectrometer Polarization (CASPOL) instrument

2012 ◽  
Vol 12 (8) ◽  
pp. 22415-22449 ◽  
Author(s):  
A. Glen ◽  
S. D. Brooks
Keyword(s):  
Cross Sections ◽  
Atmospheric Aerosols ◽  
Single Particle ◽  
Global Climate ◽  
Optical Scattering ◽  
Measurement Tool ◽  
Optical Signature ◽  
New Instrument ◽  
The Difference ◽  
Atmospherically Relevant

Abstract. Atmospheric aerosols have major impacts on regional and global climate through scattering and absorption of atmospheric radiation. A new instrument, the Droplet Measurement Technologies Cloud Aerosol Spectrometer Polarization Option (CASPOL) measures light scattered by aerosols in the forward (4° to 12°) and backward (168° to 176°) directions, with an additional polarized detector in the backward direction. Scattering by a single particle can be measured by all three detectors for aerosols in a broad range of sizes, 0.6 μm < diameter < 50 μm. The CASPOL is a unique measurement tool, since very few in situ probes can measure optical properties on a particle-by-particle basis. In this study, single particle CASPOL measurements for thirteen atmospherically relevant dusts were obtained and their optical scattering signatures were evaluated. In addition, Scanning Electron Microscopy (SEM) was used to characterize the shape and morphology of each type of dust. The total and polarized backscatter intensities varied with particle size for all dust types. Using a new optical signature technique all but one dust type could be categorized into one of three optical scattering groups. Additionally, a composite method was used to derive the optical signature of Arizona Test Dust (ATD) by combining the signatures of its major components. The derived signature was consistent with the measured signature of ATD. Finally, calculated backscattering cross sections for representative dust from each of the three main groups were found to vary by as much as a factor of 7, the difference between the backscattering cross sections of white quartz (5.3 × 10−10 cm−2) and hematite (4.1 × 10−9 cm−2).

scholarly journals A new method for measuring optical scattering properties of atmospherically relevant dusts using the Cloud and Aerosol Spectrometer with Polarization (CASPOL)

2013 ◽  
Vol 13 (3) ◽  
pp. 1345-1356 ◽  
Author(s):  
A. Glen ◽  
S. D. Brooks
Keyword(s):  
Cross Sections ◽  
Atmospheric Aerosols ◽  
Single Particle ◽  
Global Climate ◽  
Optical Scattering ◽  
Measurement Tool ◽  
Optical Signature ◽  
New Instrument ◽  
The Difference ◽  
Atmospherically Relevant

Abstract. Atmospheric aerosols have major impacts on regional and global climate through scattering and absorption of solar radiation. A new instrument, the Cloud and Aerosol Spectrometer with Polarization (CASPOL) from Droplet Measurement Technologies measures light scattered by aerosols in the forward (4° to 12°) and backward (168° to 176°) directions, with an additional polarized detector in the backward direction. Scattering by a single particle can be measured by all three detectors for aerosols in a broad range of sizes, 0.6 μm < diameter < 50 μm. The CASPOL is a unique measurement tool, since unlike most in-situ probes, it can measure optical properties on a particle-by-particle basis. In this study, single particle CASPOL measurements for thirteen atmospherically relevant dusts were obtained and their optical scattering signatures were evaluated. In addition, Scanning Electron Microscopy (SEM) was used to characterize the shape and morphology of each type of dust. The total and polarized backscatter intensities varied with particle size for all dust types. Using a new optical signature technique all but one dust type could be categorized into one of three optical scattering groups. Additionally, a composite method was used to derive the optical signature of Arizona Test Dust (ATD) by combining the signatures of its major components. The derived signature was consistent with the measured signature of ATD. Finally, calculated backscattering cross sections for representative dust from each of the three main groups were found to vary by as much as a factor of 7, the difference between the backscattering cross sections of white quartz (5.3 × 10−10 cm−2) and hematite (4.1 × 10−9 cm−2).

STUDY OF IN-MEDIUM PROPERTIES OF N*(1535) AND CHIRAL SYMMETRY FOR BARYONS THROUGH THE η-MESIC NUCLEI FORMATION AT J-PARC

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2512-2515 ◽  
Author(s):  
HIDEKO NAGAHIRO ◽  
DAISUKE JIDO ◽  
SATORU HIRENZAKI
Keyword(s):  
Chiral Symmetry ◽  
Cross Sections ◽  
Optical Potential ◽  
Nuclear Medium ◽  
Nucleus Interaction ◽  
Level Crossing ◽  
Doublet Model ◽  
The Difference ◽  
Characteristic Features ◽  
Mesic Nuclei

We investigate the properties of η-nucleus interaction by postulating the N*(1535) dominance for η-N system. We evaluate the N*(1535) properties in the nuclear medium using two kinds of chiral models, and find that these two models provide qualitatively different η-nucleus optical potentials reflecting the quite distinct properties of N*(1535) in these chiral models. Especially, in the chiral doublet model, we can expect to have the level crossing between η and N*(1535)-hole which is expected to provide the characteristic features for the optical potential and the formation spectra. We find also that the difference of these models can be seen in the formation cross sections of the η mesic nuclei with (π+, p ) reaction expected to be performed at J-PARC project.

Numerical Analysis of Branch Mechanical Response to Loading

2019 ◽  
Vol 45 (4) ◽  
Author(s):  
Barbora Vojáčková ◽  
Jan Tippner ◽  
Petr Horáček ◽  
Luděk Praus ◽  
Václav Sebera ◽  
...  
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Mechanical Response ◽  
Mechanical Analysis ◽  
Beam Deflection ◽  
Design System ◽  
Elliptical Cross ◽  
Static Mechanical ◽  
The Difference ◽  
Tree Uprooting

Failure of a tree can be caused by a stem breakage, tree uprooting, or branch failure. While the pulling test is used for assessing the first two cases, there is no device-supported method to assess branch failure. A combination of the optical technique, pulling test, and deflection curve analysis could provide a device-supported tool for this kind of assessment. The aim of the work was to perform a structural analysis of branch response to static mechanical loading. The analyses were carried out by finite element simulations in ANSYS using beam tapered elements of elliptical cross-sections. The numerical analyses were verified by the pulling test combined with a sophisticated optical assessment of deflection evaluation. The Probabilistic Design System was used to find the parameters that influence branch mechanical response to loading considering the use of cantilever beam deflection for stability analysis. The difference in the branch’s deflection between the simulation and the experiment is 0.5% to 26%. The high variability may be explained by the variable modulus of the elasticity of branches. The finite element (FE) sensitivity analysis showed a higher significance of geometry parameters (diameter, length, tapering, elliptical cross-section) than material properties (elastic moduli). The anchorage rotation was found to be significant, implying that this parameter may affect the outcome in mechanical analysis of branch behavior. The branch anchorage can influence the deflection of the whole branch, which should be considered in stability assessment.

Fluid Flow and Heat Transfer of Liquid Sodium in Small-Scale Heat Sinks With Different Geometries

2021 ◽  
Author(s):  
Mahyar Pourghasemi ◽  
Nima Fathi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Cross Sections ◽  
Heat Sink ◽  
Volume Ratio ◽  
Heat Sinks ◽  
Liquid Sodium ◽  
Small Scale ◽  
Nusselt Numbers ◽  
The Difference

Abstract 3-D numerical simulations are performed to investigate liquid sodium (Na) flow and the heat transfer within miniature heat sinks with different geometries and hydraulic diameters of less than 5 mm. Two different straight small-scale heat sinks with rectangular and triangular cross-sections are studied in the laminar flow with the Reynolds number up to 1900. The local and average Nusselt numbers are obtained and compared against eachother. At the same surface area to volume ratio, rectangular minichannel heat sink leads to almost 280% higher convective heat transfer rate in comparison with triangular heat sink. It is observed that the difference between thermal efficiencies of rectangular and triangular minichannel heat sinks was independent of flow Reynolds number.

Correction method for the asymmetry of the tangential beam in Couette (or Searle) geometry used in rheo-small-angle neutron scattering

2004 ◽  
Vol 37 (3) ◽  
pp. 438-444 ◽  
Author(s):  
Florian Nettesheim ◽  
Ulf Olsson ◽  
Peter Lindner ◽  
Walter Richtering
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Correction Method ◽  
Shear Cell ◽  
The Asymmetry ◽  
The Difference ◽  
Scattering Cross Sections ◽  
Final Expression

A method of correcting the asymmetry in the scattering of the tangential beam configuration in a rheo-small-angle neutron scattering experiment is proposed. The asymmetry of the scattering in the tangential beam configuration can be attributed to the difference in pathlength for neutrons that are scattered toward compared with those which are scattered away from the axis of rotation of the shear cell. The pathlength problem is solved and a final expression for the two-dimensional scattering intensity is given. The results from these calculations are compared with experimental data, which offer a different option to correct this asymmetry, namely by just measuring the scattering of H2O/D2O mixtures with absolute scattering cross sections identical to those of the respective samples. However, the situation for anisotropic media is more complex and the correction procedure described here is less effective.

scholarly journals The IG- file use to Gauge the Apical Diameter in Endodontics: An In Vitro Study

2018 ◽  
Vol 12 (1) ◽  
pp. 638-646 ◽  
Author(s):  
Massimo Amato ◽  
Alfredo Iandolo ◽  
Giuseppe Pantaleo ◽  
Dina Abtellatif ◽  
Michele Simeone ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Reference Value ◽  
In Vitro Study ◽  
Vitro Study ◽  
Root Canals ◽  
New Instrument ◽  
Clinician Experience ◽  
Incorrect Measurement ◽  
The Difference

Aim: The aim of this study was to evaluate the efficacy of the IG-file, a new instrument designed for apical diameter gauging. Materials and Methods: After shaping with F1 Universal Protaper, 60 roots were randomly divided into two groups and assigned to two operators, One Expert in Endodontics (EO) and One Unexpert (UO). In each sample, after canal curvatures have been detected, the apical diameters were measured with the IG-file and the K-NiTi. The results were compared with the reference value obtained by retrograde apical gauging. The data were statistically analyzed. Results: Among 60 samples, 10% of errors were recorded when the IG-files were used; in the K-NiTi group the incorrect measurements were 70%. In both groups (expert and unexpert) the IG-file measurements were more accurate than the K-NiTi (90 vs 33 and 90 vs 26,7). The differences were statistically significant. In curved canals, the difference between measurement rates performed with both instruments was statistically significant (85,7% IG-file vs 28,6% K-NiTi) as well as for the samples without curvatures (92,3% IG file vs 30,8% NiTi file). In root canals without curvatures overestimation errors in K-NiTi file group are more frequent than underestimation errors. This difference was statistically significant. Conclusion: A proper gauging of the apical diameter has a key role in endodontic therapy; an incorrect measurement can lead to clinical failures. This “in vitro” study highlights that IG-file improves measurement accuracy independently from clinician experience. Furthermore, in curved canals, the IG-file is more accurate than K-NiTi.

scholarly journals Field Study of Morphological Parameters in Step-Pool Streams

2018 ◽  
Vol 4 (8) ◽  
pp. 1930 ◽  
Author(s):  
Abbas Torbizadeh ◽  
Ahmad Tahershamsi ◽  
Mohammad Reza Majdzadeh Tabatabai
Keyword(s):  
Field Study ◽  
Cross Sections ◽  
Wave Length ◽  
Step Length ◽  
Morphological Parameters ◽  
Energy Field ◽  
Intermediate Morphology ◽  
Length Step ◽  
Successive Step ◽  
The Difference

Nowadays, step-pool formations have attracted a lot of attention, which are distinguished by the successive arrangements of the bed, suitable geometry, and the tumbling flow pattern, which can highly disperse water energy. Field study of a step–pool channel, along with one of the upper reaches of Kamandan River indicated a strong correlation between several morphological parameters of the river such as reach slope, step length, step height, pool depth, local slope, and the like. The length of the reach under the study is 145 meters and has an intermediate morphology based on Montgomery and Buffington’s classification. Therefore, twelve distinct step units were identified for 145 meters upstream while the rest was formed by steep morphology. In the present study, different definitions of wave length were applied to establish the relationships among the above parameters. For instance, the difference between apexes of every two successive step elevation was found to have a considerable relationship with the wavelength with a determination coefficient of 0.9. In addition, bankfull width and depth, along the profile for different cross-sections, were determined to establish a relationship between these parameters and pool spacing. Further, the parameters were applied to create a relationship with step heights.

High spectral resolution lidar to measure optical scattering properties of atmospheric aerosols 1: Theory and instrumentation

1983 ◽  
Vol 22 (23) ◽  
pp. 3716 ◽  
Author(s):  
S. T. Shipley ◽  
D. H. Tracy ◽  
E. W. Eloranta ◽  
J. T. Trauger ◽  
J. T. Sroga ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Atmospheric Aerosols ◽  
Optical Scattering ◽  
High Spectral Resolution ◽  
High Spectral Resolution Lidar

Number of spikes in single particle ICP-MS time scans: from the very dilute to the highly concentrated range

2021 ◽  
Author(s):  
Pierre-Emmanuel Peyneau ◽  
Martin Guillon
Keyword(s):  
Single Particle ◽  
Inductively Coupled Plasma ◽  
Particle Number ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
Inductively Coupled ◽  
Nanoparticle Dispersions ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
The Difference

The particle number concentration (PNC) of dilute nanoparticle dispersions can be determined by single particle inductively coupled plasma-mass spectrometry (sp-ICP-MS). Virtually equal to zero for very dilute dispersions, the difference...

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