scholarly journals Spontaneous and Ion-Specific Formation of Inverted Bilayers at Air/Aqueous Interface

2021 ◽  
Author(s):  
Srikanth Nayak ◽  
Raju R Kumal ◽  
Ahmet Uysal
Keyword(s):  
Rare Earths ◽  
Energy Barrier ◽  
Rare Earth Metals ◽  
Chemical Separation ◽  
Interfacial Structure ◽  
Arrhenius Behavior ◽  
Temperature Dependent ◽  
Specific Effects ◽  
Kinetics Of ◽  
Conversion Temperature

Developing better separation technologies for rare earth metals is important for a sustainable economy. However, the chemical similarities between rare earths make their separations difficult. Identifying molecular scale interactions that amplify the subtle differences between the rare earths can be useful in developing new separation technologies. Here, we describe ion-dependent monolayer to inverted bilayer transformation of extractant molecules at the air/aqueous interface. The inverted bilayers form with Lu3+ ions but not with Nd3+. By introducing Lu3+ ions to preformed monolayers, we extract kinetic parameters corresponding to the monolayer to inverted bilayer conversion. Temperature-dependent studies show Arrhenius behavior with an energy barrier of 40 kcal/mol. The kinetics of monolayer to inverted bilayer conversion is also affected by the character of the background anion, although anions are expected to be repelled from the interface. Our results show the outsized importance of ion-specific effects on interfacial structure and kinetics, pointing to their role in chemical separation methods.

Influence of Rare Earth Metals on Carburizing Kinetics of 21NiCrMo2 Steel

2015 ◽  
Vol 1114 ◽  
pp. 206-213 ◽  
Author(s):  
Daniela Dragomir ◽  
Mihai Cojocaru ◽  
Leontin Druga ◽  
Zoltán Kolozsváry ◽  
Andrei Berbecaru
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Rare Earth Metals ◽  
Layer Growth ◽  
Technical Literature ◽  
Metallic Material ◽  
Thermochemical Processing ◽  
Kinetics Of

The influence of rare-earth metals adsorbed in the surface of the metallic material subject to thermochemical processing as well as of those pre-added in the material matrix on the kinetics of layers growth is presented in the technical literature. It is generally concluded that the presence of rare earths is accelerating the kinetics of layer growth.

Temperature Dependent Kinetics of the OH/HO2/O3Chain Reaction by Time-Resolved IR Laser Absorption Spectroscopy

2000 ◽  
Vol 104 (17) ◽  
pp. 3964-3973 ◽  
Author(s):  
Sergey A. Nizkorodov ◽  
Warren W. Harper ◽  
Bradley W. Blackmon ◽  
David J. Nesbitt
Keyword(s):  
Absorption Spectroscopy ◽  
Laser Absorption Spectroscopy ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Laser Absorption ◽  
Ir Laser ◽  
Kinetics Of

Kinetics of mixed rare earths minerals decomposed by CaO with NaCl-CaCl2 melting salt

2010 ◽  
Vol 28 ◽  
pp. 86-90 ◽  
Author(s):  
Xue BIAN ◽  
Jianli CHEN ◽  
Zhihua ZHAO ◽  
Shaohua YIN ◽  
Yao LUO ◽  
...  
Keyword(s):  
Rare Earths ◽  
Kinetics Of

scholarly journals Kinetics of gluten protein-insolubilisation during pasta processing: Decoupling between time- and temperature-dependent effects

2019 ◽  
Vol 88 ◽  
pp. 103-109 ◽  
Author(s):  
Coline Martin ◽  
Marie-Hélène Morel ◽  
Adrien Reau ◽  
Bernard Cuq
Keyword(s):  
Gluten Protein ◽  
Temperature Dependent ◽  
Kinetics Of

Oxygen Absorption Kinetics of Sheets and Films Containing a Commercial Iron-based Oxygen Scavenger

2009 ◽  
Vol 15 (2) ◽  
pp. 159-168 ◽  
Author(s):  
M.J. Galotto ◽  
S.A. Anfossi ◽  
A. Guarda
Keyword(s):  
Relative Humidity ◽  
Kinetic Parameters ◽  
Oxygen Absorption ◽  
Absorption Kinetics ◽  
Oxygen Scavenger ◽  
Arrhenius Behavior ◽  
Oxygen Scavengers ◽  
Iron Based ◽  
Empirical Growth ◽  
Kinetics Of

Absorption kinetics of three different forms of the same iron-based oxygen scavenger were studied. Oxygen scavengers were used as pellet, sheet, and film materials. Two scavenger concentrations were used for sheet and film forms. Scavenger samples were analyzed at 75 or 100% relative humidities and stored at 5, 15, and 25°C. Oxygen concentration in the headspace was measured as a function of time. Absorption kinetics was best described by the Chapman-Richards empirical growth model rather than by a first-order reaction. Arrhenius behavior was observed for variations in the final absorption rate with temperature. Absorption capacities, final absorption rates, and activation energies were evaluated and discussed. Scavenger concentration, relative humidity, and temperature effects on kinetic parameters were studied for each experimental condition. Temperature was the most important factor that affected kinetic parameters. At the relative humidity levels studied, any important effect on kinetic parameters was not observed, except on absorption capacities.

An Alternative Approach to Analyzing the Interstitial Decay from the End of Range Damage During Millisecond Annealing

2008 ◽  
Vol 1070 ◽  
Author(s):  
Renata Camillo-Castillo ◽  
Mark E Law ◽  
Kevin S Jones
Keyword(s):  
Annealing Time ◽  
Dwell Time ◽  
Extended Defects ◽  
Temperature Dependent ◽  
Temperature Regimes ◽  
Alternative Approach ◽  
Small Times ◽  
Conventional Annealing ◽  
Kinetics Of ◽  
Anneal Temperature

ABSTRACTFlash-assist Rapid Thermal Processing (RTP) presents an opportunity to investigate annealing time and temperature regimes which were previously not accessible with conventional annealing techniques such as Rapid Thermal Annealing. This provides a unique opportunity to explore the early stages of the End of Range (EOR) damage evolution and also to examine how the damage evolves during the high temperature portion of the temperature profile. However, the nature of the Flash-assist RTP makes it is extremely difficult to reasonably compare it to alternative annealing techniques, largely because the annealing time at a given temperature is dictated by the FWHM of the radiation pulse. The FWHM for current flash tools vary between 0.85 and 1.38 milliseconds, which is three orders of magnitude smaller to that required for a RTA to achieve similar temperatures. Traditionally, the kinetics of the extended defects has been studied by time dependent studies utilizing isothermal anneals; in which specific defect structures could be isolated. The characteristics of Flash-assist RTP do not allow for such investigations in which the EOR defect evolution could be closely tracked with time. Since the annealing time at the target temperature for the Flash-assist RTP is essentially fixed to very small times on the order of milliseconds, isochronal anneals are a logical experimental approach to temperature dependent studies. This fact presents a challenge in the data analysis and comparison. Another feature of Flash-assist RTP which makes the analysis complex is the ramp time relative to the dwell time spent at the peak fRTP temperature. As the flash anneal temperature is increased the total ramp time can exceed the dwell time at the peak temperature, which may play a significantly larger role in dictating the final material properties. The inherent characteristics of Flash-assist RTP have consequently required the development of another approach to analyzing the attainable experimental data, such that a meaningful comparison could be made to past studies. The adopted analysis entails the selection of a reference anneal, from which the decay in the trapped interstitial density can be tracked with the flash anneal temperature, allowing for the kinetics of the interstitial decay to be extracted.

scholarly journals Temperature Dependent Seed Germination of Dalbergia nigra Allem (Leguminosae)

2001 ◽  
Vol 44 (4) ◽  
pp. 401-404 ◽  
Author(s):  
Fernanda G. A. Ferraz-Grande ◽  
Massanori Takaki
Keyword(s):  
Seed Germination ◽  
Endangered Species ◽  
High Temperatures ◽  
Broad Temperature Range ◽  
Optimum Temperature ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dalbergia Nigra ◽  
The Mean ◽  
Kinetics Of

The germination of endangered species Dalbergia nigra was studied and 30.5° C was found as optimum temperature, although the species presented a broad temperature range where germination occurs and light had no effect. The analysis of kinetics of seed germination confirmed the asynchronized germination below and above the optimum temperature. The light insensitive seed and germination also at high temperatures indicated that D. nigra could occur both in understories and gaps where the mean temperature was high.

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