Post-anneal effect on the structural and Li+ conduction properties in NaI - LiBH4 system

MRS Advances ◽  
2017 ◽  
Vol 2 (7) ◽  
pp. 389-394 ◽  
Author(s):  
Reona Miyazaki ◽  
Dai Kurihara ◽  
Daiki Hayashi ◽  
Seiya Furughori ◽  
Masatoshi Shomura ◽  
...  
Keyword(s):  
Activation Energy ◽  
Ball Milling ◽  
Ion Conductivity ◽  
The Other ◽  
Compositional Dependence ◽  
Post Annealing ◽  
Free Sample ◽  
Milled Sample ◽  
Sample Homogeneity ◽  
Conduction Properties

ABSTRACTIn the present work, NaI – LiBH4 system fabricated by ball milling were post annealed and their variation of Li+ ion conductivity were investigated. From the change of lattice parameters by post annealing, it was suggested that unreacted LiBH4 existed in as-milled sample further dissolved into NaI, which implied an enhancement of the sample homogeneity. On the other hand, the segregation of LiI was anticipated when ball milled 15NaI·LiI (BH4 free sample) was annealed at 423 K. Li+ conductivity was decreased by post anneal process and compositional dependence of an activation energy for Li+ conduction was indicated for the homogeneous NaI – LiBH4 system.

Fabrication of TiH2 Powders from Titanium Tuning Chip by Mechanical Milling

2007 ◽  
Vol 534-536 ◽  
pp. 185-188 ◽  
Author(s):  
Jin Man Jang ◽  
Won Sik Lee ◽  
Se Hyun Ko
Keyword(s):  
Activation Energy ◽  
Ball Milling ◽  
Titanium Hydride ◽  
Mechanical Milling ◽  
The Other ◽  
Titanium Hydride Powder ◽  
Manufacturing Technologies ◽  
Short Time ◽  
Hydride Powder

In present work, manufacturing technologies of titanium hydride powder were studied for recycling of titanium tuning chip and for this, attrition ball milling was carried out under H2 pressure of 0.5 MPa. Ti chips were completely transformed into TiH2 within several hundred seconds that is very short time comparing to that in the previous report. Dehydrogenation process TiH2 powders is consist of two reactions: one is reaction of TiH2 to TiHx and the other decomposition of TiHx to Ti and H2. The former reaction shows relatively low activation energy ranged from about 100 KJ/mol to 250 KJ/mol and it is suggested that the reaction is caused by introduction of defects due to milling. In case of TiH2 powders that hardly contains defects, decomposition of TiH2 to Ti and H2 occurs directly without the reaction of TiH2 to TiHx and activation energy is very large as much as 929 KJ/mol.

scholarly journals Li2(BH4)(NH2) Nanoconfined in SBA-15 as Solid-State Electrolyte for Lithium Batteries

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 946
Author(s):  
Qianyi Yang ◽  
Fuqiang Lu ◽  
Yulin Liu ◽  
Yijie Zhang ◽  
Xiujuan Wang ◽  
...  
Keyword(s):  
Solid State ◽  
High Performance ◽  
Coulombic Efficiency ◽  
Specific Capacity ◽  
Transference Number ◽  
Electrochemical Stability ◽  
Ion Conductivity ◽  
Solid State Batteries ◽  
Li Ion ◽  
Conduction Properties

Solid electrolytes with high Li-ion conductivity and electrochemical stability are very important for developing high-performance all-solid-state batteries. In this work, Li2(BH4)(NH2) is nanoconfined in the mesoporous silica molecule sieve (SBA-15) using a melting–infiltration approach. This electrolyte exhibits excellent Li-ion conduction properties, achieving a Li-ion conductivity of 5.0 × 10−3 S cm−1 at 55 °C, an electrochemical stability window of 0 to 3.2 V and a Li-ion transference number of 0.97. In addition, this electrolyte can enable the stable cycling of Li|Li2(BH4)(NH2)@SBA-15|TiS2 cells, which exhibit a reversible specific capacity of 150 mAh g−1 with a Coulombic efficiency of 96% after 55 cycles.

scholarly journals Removal of Chromium from Aqueous Solution Using Modified Pomegranate Peel:Mechanistic and Thermodynamic Studies

2009 ◽  
Vol 6 (s1) ◽  
pp. S153-S158 ◽  
Author(s):  
Tariq S. Najim ◽  
Suhad A. Yassin
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Aqueous Solution ◽  
Adsorption Process ◽  
Batch Process ◽  
The Other ◽  
Water Molecules ◽  
Pomegranate Peel ◽  
Solution Interface ◽  
Adsorbent Surface

Modified pomegranate peel (MPGP) and formaldehyde modified pomegranate peel (FMPGP) were prepared and used as adsorbent for removal of Cr(VI) ions from aqueous solution using batch process. The temperature variation study of adsorption on both adsorbents revealed that the adsorption process is endothermic, from the positive values of ∆H˚. These values lie in the range of physisorption. The negative values of ∆G˚ show the adsorption is favorable and spontaneous. On the other hand, these negative values increases with increase in temperature on both adsorbents, which indicate that the adsorption is preferable at higher temperatures. ∆S˚ values showed that the process is accompanied by increase in disorder and randomness at the solid solution interface due to the reorientation of water molecules and Cr(VI) ions around the adsorbent surface. The endothermic nature of the adsorption was also confirmed from the positive values of activation energy, Ea, the low values of Ea confirm the physisorption mechanism of adsorption. The sticking probability, S*, of Cr(VI) ion on surface of both adsorbents showed that the adsorption is preferable due to low values of S*(0< S*< 1 ), but S*values are lower for FMPGP indicating that the adsorption on FMPGP is more preferable .

Synthesis by High-Energy Ball Milling of MgH2-TiFe Composites for Hydrogen Storage

2017 ◽  
Vol 899 ◽  
pp. 13-18 ◽  
Author(s):  
Ricardo Mendes Leal Neto ◽  
Rafael de Araújo Silva ◽  
Ricardo Floriano ◽  
Graziele Cristina Seco Coutinho ◽  
Railson Bolsoni Falcão ◽  
...  
Keyword(s):  
Ball Milling ◽  
Hydrogen Absorption ◽  
Hydrogen Desorption ◽  
High Energy ◽  
Control Agent ◽  
High Energy Ball Milling ◽  
Absorption Kinetics ◽  
Particle Size Reduction ◽  
Milled Sample ◽  
Energy Ball

The aim of this work is to investigate the influence of some processes variables on the microstructure and hydrogen absorption kinetics of MgH2 - X wt.% TiFe composites. Samples were synthesized by high-energy ball milling in a planetary (X = 40, 50, 60) and shaker mill (X = 40) under high-purity argon atmosphere. Commercial MgH2 instead of Mg powder was used in order to reduce adherence on the vial and balls. TiFe powder was previously produced by ball milling a mixture of TiH2 and Fe powders followed by a reaction synthesis at 600oC. Milled composites samples were characterized by XRD and SEM analysis. Milling time was preliminary investigated (X = 40) in the planetary ball mill (6 to 36h). TiFe particle size reduction was shown to be difficult since they are surrounded by MgH2 matrix. Strong particle reduction was obtained by using a shaker mill only for 2 hours and adding cyclohexane as process control agent. No reaction between MgH2 and TiFe compound was observed in any milled sample. Hydrogen absorption kinetics measurements of the as-milled samples were conducted on an Sieverts' type apparatus at room temperature after hydrogen desorption at 350oC under vacuum. The best hydrogen kinetics (3 wt% at the first hour) was attained by the planetary milled sample (36 h). Higher hydrogen capacity was observed for the sample milled in the shaker mill (4.0 wt.%), but only after 13h.

Synthesis of Fe-rich Fe–Al nanocrystalline solid solutions using ball milling

1999 ◽  
Vol 14 (5) ◽  
pp. 1760-1770 ◽  
Author(s):  
H. G. Jiang ◽  
H. M. Hu ◽  
E. J. Lavernia
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Thermal Stability ◽  
Intermetallic Compound ◽  
Ball Milling ◽  
Microstructural Evolution ◽  
Solid Solutions ◽  
Al Alloys ◽  
Time Intervals ◽  
Thermal Stability Of

The synthesis of nanocrystalline Fe, Fe–4 wt% Al, and Fe–10 wt% Al solid solutions by SPEX ball milling has been studied. The microstructural evolution during ball milling, as well as subsequent heat treatment, has been characterized. The results demonstrate that ball milling promotes the formation of αFe–4 wt% Al and αFe–10 wt% Al solid solutions by reducing the activation energy of these alloys and generating thermal energy during this process. For Fe–10 wt% Al powders milled for various time intervals up to approximately 20 min, the FeAl intermetallic compound is formed. For alloys annealed at temperatures ranging from 600 to 1000 °C, the addition of 10 wt% Al to Fe significantly enhances the thermal stability of the nanocrystalline Fe–Al alloys. Interestingly, the addition of Al within the range of 4–10 wt% seems to have little effect on the thermal stability of these alloys annealed under the same conditions. Also, the thermal stability improves for alloys milled in air as opposed to those processed using Ar.

Conduction blocks in and around preferential pathway of dog right atrium

1987 ◽  
Vol 253 (1) ◽  
pp. H16-H24 ◽  
Author(s):  
K. Yamashita ◽  
M. Hiraoka ◽  
H. Adaniya
Keyword(s):  
Right Atrium ◽  
Cycle Length ◽  
Conduction Block ◽  
Longitudinal Direction ◽  
The Other ◽  
Histological Findings ◽  
Crista Terminalis ◽  
Histological Studies ◽  
High K ◽  
Conduction Properties

We studied conduction properties and histological findings at branching sites of the pectinate muscle (PM) from the crista terminalis (CT) in the dog right atrium. Propagation was faster in the longitudinal direction along CT than along PM. When the rate of stimulation was increased, conduction blocks to PM occurred at a longer cycle length than those to CT in 10 of 19 cases without differences in the refractory period. There were two block sites, one at the lateral edge within CT and the other at the branching site of PM from CT. The former was dominant with normal solution and the latter with high K+ solution. Histological studies showed no apparent differences between the two groups. CT consisted of a number of unit bundles in a longitudinal direction. The unit bundles continuing from the edge of CT proceeded into PM. Their orientation in PM, however, became irregular and tangled. Between the branches of PM, conduction block occurred unpredictably without regard to direction. These observations indicated the importance of the arrangement and orientation of the unit bundles in the appearance of the preferential conduction and block.

Effect of storage temperature on the microbial and color stability of banana purée with addition of vanillin or potassium sorbate / Efecto de la temperatura de almacenamiento en la estabilidad microbiológica y en el color del puré de plátano con la adición de vainillina o sorbato de potasio

1999 ◽  
Vol 5 (1) ◽  
pp. 51-58 ◽  
Author(s):  
X. Castañón ◽  
A. Argaiz ◽  
A. López-Malo
Keyword(s):  
Activation Energy ◽  
Free Energy ◽  
Microbial Growth ◽  
Storage Temperature ◽  
Color Stability ◽  
The Other ◽  
Potassium Sorbate ◽  
Native Flora ◽  
Color Changes ◽  
Different Temperatures

The microbial and color changes during storage at different temperatures (15, 25 and 35 °C) of ba nana purée preserved by the combination of a blanching, reduced pH (3.4) and water activity ( aw, 0.97) and the addition of 1000 or 3000 ppm of vanillin (VA) or 1000 ppm potassium sorbate (PS) were evaluated and compared. The use of 3000 ppm VA or 1000 ppm PS inhibited for at least 60 days of storage the native flora of the banana purée at any of the temperatures studied. The addition of 1000 ppm VA was not enough to stop the microbial growth. However, at 15 °C the growth was delayed 16 days. In the presence of 3000 ppm VA or 1000 ppm PS the banana purée stored at 15, 25 and 35 °C presented several color changes that contributed to browning. The rate of browning was greater in samples with VA than in those formulated with PS, but the activation energy was 10% lower in the former systems. An analysis of the transition state parameters revealed that Gibbs free energy was similar, indicating that the mechanism of browning did not change in the presence of one antimicro bial or the other.

scholarly journals Order vs. disorder—a huge increase in ionic conductivity of nanocrystalline LiAlO2 embedded in an amorphous-like matrix of lithium aluminate

2014 ◽  
Vol 2 (47) ◽  
pp. 20295-20306 ◽  
Author(s):  
D. Wohlmuth ◽  
V. Epp ◽  
P. Bottke ◽  
I. Hanzu ◽  
B. Bitschnau ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Ion Conductivity ◽  
Lithium Aluminate ◽  
The Poor ◽  
Energy Ball

The poor ion conductivity of LiAlO2 can be drastically enhanced via the introduction of defects or amorphisation during high-energy ball milling.

Diffusion in High Occupancy Zeolites

1987 ◽  
Vol 111 ◽  
Author(s):  
James Wei
Keyword(s):  
Activation Energy ◽  
Random Walk ◽  
Small Molecules ◽  
Irreversible Thermodynamics ◽  
Low Energy ◽  
The Other ◽  
Diffusion Region ◽  
Channel Diameter ◽  
One Dimensional ◽  
Activation Energy Of Diffusion

AbstractDiffusion of small molecules in zeolites most often takes place in the configurational diffusion region, where the molecular diameter is approximately the same or slightly greater than the channel diameter. Since two molecules may not pass each other in a pore, the random walk based diffusion equation does not apply under high occupancy conditions in zeolites with one-dimensional pores.For zeolites with multi-dimensional pores, such as ZSM-5 and A, one sometimes encounters the counter-intuitive result that diffusivity dramatically rises with occupancy. There are two explanations for this behavior: one from irreversible thermodynamics and the Darken equation, which predicts that diffusivity will always rise with occupancy; the other from a Markov model of random activated jumps between low energy positions, such as pore crossings, which predicts that diffusivity will increase with occupancy if the activation energy of diffusion decreases with occupancy– such as due to swelling.

THE ACTIVATION ENERGY FOR THE RECOMBINATION OF TRIFLUOROMETHYL RADICALS

1960 ◽  
Vol 38 (2) ◽  
pp. 182-186 ◽  
Author(s):  
G. O. Pritchard ◽  
J. R. Dacey
Keyword(s):  
Activation Energy ◽  
Activation Energies ◽  
The Other ◽  
Radical Recombination

By photolyzing mixtures of acetone and hexafluoroacetone, and measuring the rates of formation of the three ethanes, we have found [Formula: see text] which means that the activation energy for the recombination of CF3 radicals is 2140 ± 200 cal, assuming zero activation energies for the other two radical recombinations, and that none of the ethanes is formed except by radical recombination.

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