Modal And Diffusion Characterization Of K+Na+ Exchanged Glass Waveguides

1987 ◽  
Author(s):  
S. I. Najafi ◽  
J. Lapierre ◽  
R. Maciejko ◽  
F. Seguin ◽  
A. Champagne ◽  
...  
Keyword(s):  
Glass Waveguides ◽  
And Diffusion

scholarly journals Biosorption and Diffusion Modeling of Pb(II) by Malt Bagasse

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Klaiani B. Fontana ◽  
Giane Gonçalves Lenzi ◽  
Erica R. L. R. Watanabe ◽  
Ervin Kaminski Lenzi ◽  
Juliana A. M. T. Pietrobelli ◽  
...  
Keyword(s):  
Sorption Process ◽  
Isotherm Models ◽  
Diffusion Modeling ◽  
Biosorption Capacity ◽  
Kinetic And Thermodynamic Parameters ◽  
Pseudo Second Order ◽  
Ph Optimization ◽  
Kinetics Of ◽  
And Diffusion

The removal of Pb(II) from water by biosorption processes onto malt bagasse was investigated and the kinetic and thermodynamic parameters were obtained; additionally a diffusion modeling was proposed. The characterization of malt bagasse was performed by FTIR and SEM/EDS. The experiments were conducted in batch system and an experimental design based response surface methodology was applied for agitation speed and pH optimization. The kinetics of biosorption followed pseudo-second-order model and the temperature of the process affected the biosorption capacity. Isotherm models of Langmuir, Freundlich, and Elovich were applied and the Langmuir model showed better fit and the estimated biosorption capacity was 29.1 mg g−1. The negative values obtained for ΔG° and positive values of ΔH° confirm, respectively, the spontaneous and endothermic nature of the process. The diffusion modeling was performed based on experiments in the absence of agitation to investigate the influence of the biosorbent on the sorption process of Pb(II) ions.

Characterization of multiple sclerosis neuroinflammation and neurodegeneration with relaxation and diffusion basis spectrum imaging

2021 ◽  
pp. 135245852110233
Author(s):  
Irene M Vavasour ◽  
Peng Sun ◽  
Carina Graf ◽  
Jackie T Yik ◽  
Shannon H Kolind ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Specific Information ◽  
Axonal Loss ◽  
Normal Appearing White Matter ◽  
Relapsing Remitting ◽  
Tissue Changes ◽  
Spectrum Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
And Diffusion

Background: Advanced magnetic resonance imaging (MRI) methods can provide more specific information about various microstructural tissue changes in multiple sclerosis (MS) brain. Quantitative measurement of T1 and T2 relaxation, and diffusion basis spectrum imaging (DBSI) yield metrics related to the pathology of neuroinflammation and neurodegeneration that occurs across the spectrum of MS. Objective: To use relaxation and DBSI MRI metrics to describe measures of neuroinflammation, myelin and axons in different MS subtypes. Methods: 103 participants (20 clinically isolated syndrome (CIS), 33 relapsing-remitting MS (RRMS), 30 secondary progressive MS and 20 primary progressive MS) underwent quantitative T1, T2, DBSI and conventional 3T MRI. Whole brain, normal-appearing white matter, lesion and corpus callosum MRI metrics were compared across MS subtypes. Results: A gradation of MRI metric values was seen from CIS to RRMS to progressive MS. RRMS demonstrated large oedema-related differences, while progressive MS had the most extensive abnormalities in myelin and axonal measures. Conclusion: Relaxation and DBSI-derived MRI measures show differences between MS subtypes related to the severity and composition of underlying tissue damage. RRMS showed oedema, demyelination and axonal loss compared with CIS. Progressive MS had even more evidence of increased oedema, demyelination and axonal loss compared with CIS and RRMS.

Experimental Characterization of Vaneless Diffuser Rotating Stall: Part VI — Reduction of Three Impeller Results

2006 ◽  
Author(s):  
E. A. Carnevale ◽  
G. Ferrara ◽  
L. Ferrari ◽  
L. Baldassarre
Keyword(s):  
Rotating Stall ◽  
Radius Ratio ◽  
Vaneless Diffuser ◽  
Cross Sectional ◽  
Stall Inception ◽  
Return Channel ◽  
Geometrical Scale ◽  
And Diffusion ◽  
Basic Configuration

Vaneless diffuser rotating stall is a major problem for centrifugal compressors since it is a limit to their working range. In the literature some good correlations for predicting stall inception can be found but they do not adequately cover the case of the last stage configuration, especially for very low blade-outlet-width-to-impeller-radius-ratio impellers typically used in high-pressure applications. Extensive research has been performed to define diffuser stall limits for this family of stages: three impellers characterized by different blade-outlet-width-to-impeller-radius-ratios have been tested with different diffuser configurations (different pinch shapes, diffuser widths and diffusion ratios). The basic configuration comprises a 1:1 geometrical scale stage with a return channel upstream, a 2D impeller with a vaneless diffuser and a volute with a constant cross sectional area downstream. Several diffuser types with different widths and diffusion ratios were tested. Detailed experimental results have been reported in previous works [1, 2, 3 and 4]. In this paper experimental data are reviewed in order to analyze impeller influence on diffuser stability and to develop some summarizing consideration on stall behavior of vaneless diffuser for impeller with low blade-outlet-width-to-impeller-radius-ratio.

scholarly journals Characterization of Halogen Bonded Adducts in Solution by Advanced NMR Techniques

2017 ◽  
Author(s):  
Gianluca Ciancaleoni
Keyword(s):  
Nuclear Overhauser Effect ◽  
Halogen Bonding ◽  
X Ray Crystallography ◽  
Diffusion Nmr ◽  
Overhauser Effect ◽  
Crucial Information ◽  
Nmr Techniques ◽  
Nuclear Overhauser ◽  
And Diffusion

In the last 20 years, a huge amount of experimental results about halogen bonding (XB) has been produced. Most of the systems have been characterized by solid state X-ray crystallography, whereas in solution the only routine technique is the titration (by using 1H and 19F NMR, IR, UV-Vis or Raman spectroscopies, depending on the nature of the system), with the aim of characterizing the strength of the XB interaction. Unfortunately, the titration techniques have many intrinsic limitations and they should be coupled with other, more sophisticated techniques to have an accurate and detailed description of the geometry and stoichiometry of the XB adduct in solution. In this review, it will be shown how crucial information about XB adducts can be obtained by advanced NMR techniques, as Nuclear Overhauser Effect-based Spectroscopies (NOESY, ROESY, HOESY…) and diffusion NMR techniques (PGSE or DOSY).

Nonlinear Optical Characterization of Gorilla® Glass Waveguides

2017 ◽  
Author(s):  
Franciele Henrique ◽  
Gustavo F. B. Almeida ◽  
Jonathas P. Siqueira ◽  
Renato J. Martins ◽  
Cleber R. Mendonça
Keyword(s):  
Nonlinear Optical ◽  
Optical Characterization ◽  
Glass Waveguides

Preparation and Characterization of Ni/ZrCoCe Stack Getter Films

2019 ◽  
Vol 944 ◽  
pp. 619-624
Author(s):  
Peng Yuan ◽  
Yao Zong Sui ◽  
Xiao Zhang ◽  
Hao Liu ◽  
Feng Wei ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Magnetron Sputtering ◽  
Film Surface ◽  
Protective Layer ◽  
Sem Analysis ◽  
And Diffusion ◽  
Highly Porous ◽  
Scanning Electron

In order to improve the oxidation resistance of the ZrCoCe getter, highly porous Ni/ZrCoCe stack getter films were grown by the magnetron sputtering method. Scanning electron microscope (SEM) analysis indicate that the Ni/ZrCoCe stack film is composed of isolated columns. The film surface with cauliflower-like topography is formed among finely packed nanocrystals. Gas sorption investigation shows that the Ni/ZrCoCe stack film can be activated at 300 °C for 30 min and exhibits more favorable sorption capability than ZrCoCe bi-layered film. XPS results show that the Ni protective layer can play an important role in protecting the ZrCoCe film against oxidation. It can also improve the surface dissociation and diffusion of H2.

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