scholarly journals Examination and experimental constraints of the stellar reaction rate factorNA〈σv〉of the18Ne(α,p)21Na reaction at temperatures of x-ray bursts

2013 ◽  
Vol 87 (3) ◽  
Author(s):  
P. Mohr ◽  
A. Matic
Keyword(s):  
Reaction Rate ◽  
X Ray ◽  
Stellar Reaction Rate

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

scholarly journals Methyl Iodide Adsorption on Reduced Silver-Functionalized Silica Aerogel: How Temperature Impacts the Adsorption?

2021 ◽  
Author(s):  
Siqi Tang ◽  
Seungrag Choi ◽  
Lawrence Tavlarides
Keyword(s):  
Methyl Iodide ◽  
Photoelectron Spectroscopy ◽  
Silica Aerogel ◽  
Reaction Rate ◽  
Reaction Pathway ◽  
Effect Of Temperature ◽  
Functionalized Silica ◽  
Contributing Factors ◽  
X Ray ◽  
Temperature Impacts

To understand the effect of temperature to the adsorption, 104 ppbv and 1044 ppbv methyl iodide (CHI) adsorptions on reduced silver-functionalized silica aerogel (Ag-Aerogel) at 100, 150 and 200 ℃ were performed. In the experiments, a significantly high uptake rate (3 – 4 times higher than that at 100 and 150 ℃) was observed for the 104 ppbv adsorption at 200 ℃. To explain such behavior, a potential reaction pathway was proposed and multiple physical analyses including nitrogen titration, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were performed. Based on the results, the contributing factors appear to be the formation of different Ag-I components induced by temperature, higher silver site availability, decreasing diffusion limitation, and increasing reaction rate described by the Arrhenius relationship.

scholarly journals Study of UiO-66 and UiO-66 Modulated with Acetic Acid as the Adsorbent for Eriochrome Black T Dye

2021 ◽  
Vol 8 (3) ◽  
pp. 183-193
Author(s):  
M. Anugrah Rizky Pambudi ◽  
Nanda Prayogo ◽  
Muhammad Nadjib ◽  
Ratna Ediati
Keyword(s):  
Acetic Acid ◽  
Reaction Rate ◽  
Metal Organic Framework ◽  
X Ray Diffraction ◽  
Adsorption Selectivity ◽  
X Ray ◽  
Langmuir Adsorption ◽  
Eriochrome Black T ◽  
Metal Organic ◽  
Pseudo Second Order

UiO-66, as one of the metal-organic framework (MOF) compounds, has been used to treat some anionic and cationic dye waste. In order to determine the adsorption selectivity decisively, the synthesis of UiO-66 and UiO-66 modulated with acetic acid had been carried out, along with their adsorption tests for Eriochrome Black T (EBT) dye solution. The synthesis was performed by utilizing a solvothermal method with the reaction mixtures of zirconium (IV) chloride (ZrCl4) and terephthalic acid (H2BDC) as a ligand heated at 120 oC for 24 hours. Both UiO-66 (without acetic acid) and acetic acid modulated UiO-66 were obtained as a white powder. Acetic acid as a modulator was added and being investigated for the adsorption capability compared to the normal UiO-66. This study showed that normal UiO-66 exhibited better adsorption than acetic acid modulated UiO-66 with a mmol ratio of acetic acid:ligand varied from 50:1, 100:1, and 150:1. Acetic acid modulated UiO-66 with a mmol ratio of 50 exhibited the best crystallinity as observed by using x-ray diffraction. It can be concluded that the adsorption of EBT using normal and acetic acid modulated UiO-66 obeyed the pseudo-second-order reaction rate law as well as the Langmuir adsorption isotherm pattern.

scholarly journals Total Cross Section of the n+11B Reaction

2020 ◽  
Vol 4 ◽  
pp. 13
Author(s):  
G. Galios ◽  
G. Doukelis ◽  
S. Kossionides ◽  
T. Paradellis
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Reaction Rate ◽  
Neutron Cross Section ◽  
Total Neutron ◽  
Cross Section Data ◽  
Total Neutron Cross Section ◽  
Section Data ◽  
Upper Limit ◽  
Stellar Reaction Rate

The total neutron cross section of 11Β has been measured from 7.2 to 8.4 MeV. The analysis of all data from the 8Li(α,n0)11Β reaction in combination with the total cross section data can determine an upper limit on the stellar reaction rate of the 8Li(a,n)11Β reaction.

Stellar Reaction Rate of 14N(p,γ)15O+

1986 ◽  
pp. 431-434 ◽  
Author(s):  
U. Schröder ◽  
H. W. Becker ◽  
J. Görres ◽  
C. Rolfs ◽  
H. P. Trautvetter ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Stellar Reaction Rate

Deactivation of Alumina Supported Catalysts Due to Spinel Formation

1994 ◽  
Vol 344 ◽  
Author(s):  
P. H. Bolt ◽  
M. E. Van Ipenburg ◽  
J. W. Geus ◽  
F. H. P. M. Habraken
Keyword(s):  
Transition Metal ◽  
Reaction Rate ◽  
Rutherford Backscattering Spectrometry ◽  
Supported Catalysts ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spinel Formation ◽  
Transition Metal Element ◽  
Metal Element

AbstractAn important cause of deactivation of alumina supported transition metal (oxide) catalysts is a solid state reaction between the active component and the support. We therefore studied the hightemperature behavior of Me layers (Me = Co, Ni, Cu and Fe) on polycrystalline α-A12O3 and γ- Al2O3 substrates. The samples were first oxidized at moderate temperatures and then annealed at high temperatures (up to 1000 °C) in O2, N2, or N2/O2 mixtures. The interfacial reaction to MeA12O4 was assessed using Rutherford Backscattering Spectrometry and X-ray diffraction. The reaction rate strongly depends on the transition metal element Me: Fe < Ni < Co < Cu. Low oxygen pressures favour spinel formation. γ-A12O3 shows a much higher reactivity towards the MeOx overlayers than α-Al2O3.

Mechanochemical reactions in the system FeTiO3–Si

1998 ◽  
Vol 13 (12) ◽  
pp. 3499-3503
Author(s):  
Ying Chen ◽  
J. S. Williams
Keyword(s):  
Room Temperature ◽  
Reaction Rate ◽  
Thermal Analyses ◽  
Mechanochemical Reaction ◽  
X Ray Diffraction ◽  
Reaction Stage ◽  
X Ray ◽  
Powder Composition ◽  
Si Content ◽  
Mechanochemical Reactions

Mechanochemical reactions in the system FeTiO3 –Si have been investigated as functions of the powder composition and milling conditions, using x-ray diffraction and thermal analyses. Reduction reactions of FeTiO3 by Si were observed during room-temperature milling with the formation of α–Fe, amorphous SiOx, nanocrystalline TiO2, or intermetallic compounds, depending on the Si content. The mechanochemical reaction process consists of a mechanical activation stage and a reaction stage. Higher milling intensity leads to a shorter activation step and a higher reaction rate.

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