Basic Experiment on Lithium Removal Technique

Author(s):  
Tomohiro Furukawa ◽  
Yasushi Hirakawa

As a preliminary investigation into the establishment of a lithium removal technique for the components used at the International Fusion Materials Irradiation Facility (IFMIF), experiments were performed on the dissolution of lithium in three solvents: ethanol, pure water, and ethanol–water. In these experiments, hemispherical lithium was immersed in the solvents at constant temperatures, and the degree of dissolution was measured continuously from the height of the sample. From the obtained data, the average dissolution rate in the solvents at each testing temperature (10–90 °C) and the amount of hydrogen generated by the chemical reaction were calculated. The average dissolution rates in ethanol, pure water, and ethanol–water at 30 °C were 0.01, 1.6, and 0.43 mm/min, respectively. Although the average dissolution rate increased with the testing temperature in the low-temperature range (10–50 °C) for all solvents, this increase was saturated in the high-temperature range (50–90 °C) in experiments with pure water and ethanol–water as solvents. The volume of gas collected during each experiment was in good agreement with the volume of hydrogen assumed to be generated from the chemical reaction of lithium with the solvents.

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Jing Zhang ◽  
Rui Ye ◽  
Jun Zou ◽  
Jijun Tang ◽  
Hongliang Wang

The isothermal curing of polymethacrylimide (PMI) is studied through the use of dynamic mechanical analysis (DMA). Based on the growth rate of measured dynamic mechanical property, the relative conversion is defined to investigate the evolution of storage modulusE′at different curing temperatures. Hsich’s nonequilibrium thermodynamic fluctuation theory, Avrami equation, and isoconversional methods are used to analyze isothermal cure kinetics of PMI. The results show that there are different increase modes ofE′at low temperature range and high temperature range, respectively. In low temperature range, the relative conversion curves include a transitional stage which is found to be strongly frequency-dependent, but this stage is not observed in the relative conversion curve in high temperature range. During the isothermal curing process, the relative evolution ofE′can be described by Hsich’s nonequilibrium thermodynamic fluctuation theory and Avrami equation. Moreover, the values and evolutions of activation energy are different in two temperature ranges, which suggest that the curing mechanism probably has changed.


2020 ◽  
Vol 239 ◽  
pp. 14006
Author(s):  
Tim Ware ◽  
David Hanlon ◽  
Tara Hanlon ◽  
Richard Hiles ◽  
Malcolm Lingard ◽  
...  

Until recently, criticality safety assessment codes had a minimum temperature at which calculations can be performed. Where criticality assessment has been required for lower temperatures, indirect methods, including reasoned argument or extrapolation, have been required to assess reactivity changes associated with these temperatures. The ANSWERS Software Service MONK® version 10B Monte Carlo criticality code, is capable of performing criticality calculations at any temperature, within the temperature limits of the underlying nuclear data in the BINGO continuous energy library. The temperature range of the nuclear data has been extended below the traditional lower limit of 293.6 K to 193 K in a prototype BINGO library, primarily based on JEFF-3.1.2 data. The temperature range of the thermal bound scattering data of the key moderator materials was extended by reprocessing the NJOY LEAPR inputs used to produce bound data for JEFF-3.1.2 and ENDF/B-VIII.0. To give confidence in the low temperature nuclear data, a series of MONK and MCBEND calculations have been performed and results compared against external data sources. MCBEND is a Monte Carlo code for shielding and dosimetry and shares commonalities to its sister code MONK including the BINGO nuclear data library. Good agreement has been achieved between calculated and experimental cross sections for ice, k-effective results for low temperature criticality benchmarks and calculated and experimentally determined eigenvalues for thermal neutron diffusion in ice. To quantify the differences between ice and water bound scattering data a number of MONK criticality calculations were performed for nuclear fuel transport flask configurations. The results obtained demonstrate good agreement with extrapolation methods. There is a discernible difference in the use of ice and water data.


2007 ◽  
Vol 351 ◽  
pp. 189-194 ◽  
Author(s):  
K. Wang ◽  
Zheng Yi Fu ◽  
Wei Min Wang ◽  
Yu Cheng Wang ◽  
H. Wang ◽  
...  

Combustion synthesis of titanium diboride(TiB2) from titanium(Ti) and boron(B) powders was studied by theoretical calculation and experimental analysis. In high temperature range or in low temperature range, the calculated activation energies are 140KJ/mol or 355KJ/mol respectively, which is described by a change from dissolution-precipitation controlled process to diffusion-controlled process. With the increase of particle size of the raw materials, combustion temperature and propagating rate will both reduce. The propagating rate decreases with the addition of diluents. Further increase of diluents may result in a stop of the combustion wave halfway or even a failure of ignition.


2021 ◽  
Author(s):  
Yan Zhao ◽  
Xusheng Wang ◽  
Rui Hu ◽  
Yanxia Li

Existing optical thermometers are faced with the challenges of high sensitivity limited to a very narrow high temperature range, while also lacking low temperature sensing performance. A new linear up-conversion...


2007 ◽  
Vol 336-338 ◽  
pp. 1420-1423 ◽  
Author(s):  
Zhang Lian Hong ◽  
Hidehiro Yoshida ◽  
Taketo Sakuma

A new interpretation model, instead of classical Kohlrausch-Williams-Watt (KWW) equation, was applied to interpret stress relaxation behavior of Si3N4-Y2Si2O7 ceramics. Results revealed that the new model could obtain reasonable relaxation plastic viscosity and viscoelastic viscosity under testing temperature range of 1300°C~1575°C. From the plotted curve of viscosity vs 1/RT, an activation energy change occurred around 1500°C was found for both plastic viscosity and viscoelastic viscosity curves. This change, which indicated the microstructure change, was in good agreement with the significant decrease of high temperature strength retention property.


Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Huadong Sun ◽  
Peng Jiang ◽  
Yongling Ding ◽  
Laixue Pang ◽  
Yinbin Liu ◽  
...  

In order to systematically study and develop a type of gussasphalt (GA) mix with superior performance, namely GA-10; the effect of Qingchuan Rock Asphalt (QRA) and Trinidad Lake asphalt (TLA) on the GA-10 mix was assessed based on the study of composite natural asphalt modified gussasphalt (CNAMGA) binder. Various analytical tests were used to evaluate the engineering properties, thermal stability and microstructure of CNAMGA mix. The results indicate that the stability of QRA modified binder and TLA modified binder in the normal temperature range and the high temperature range have been improved, and the temperature susceptibility is reduced. The optimal asphalt–aggregate ratio of the GA mix is determined to be 9.7%, which has good high-temperature stability, low-temperature crack resistance and construction workability. The QRA mix has better high-temperature stability than the TLA mix, whereas the low-temperature cracking resistance of the TLA mix is better than that of the QRA mix. The two kinds of GA-10 mix have similar construction workability. The fact that the abundant fine aggregates wrapped in binder fill the coarse aggregates surface contributes to the better adhesion of the GA asphalt concrete. The distribution of aggregate and binder is relatively uniform with fewer pores, and the overall proportion of the binder is greater than that of aggregate.


1996 ◽  
Vol 453 ◽  
Author(s):  
A. R. Guo ◽  
Z. -Y. Cheng ◽  
R. S. Katiyar ◽  
Ruyan Guo ◽  
A. S. Bhalla

AbstractDielectric measurements were carried out in single crystals of KTiOPO4, KTiOAsO4, RbTiOAsO4 and CsTiOAsO4. All of the materials exhibit a clear dielectric relaxation process in the low temperature range and a conductance mechanism in the high temperature range. The dielectric relaxation process can be well described by the Debye dielectric model with an activation energies of 0.8 eV, 0.5 eV and 0.4 eV respectively. The relaxation process is associated with the deviation of the alkali ions from its ideal lattice positions. The high temperature conductance is associated with the motion of the alkali ions from one lattice site to another. Therefore, both the low temperature relaxation process and the high temperature conductance originate from different features of defect behavior of alkali ions in the cage structure of these materials.


1994 ◽  
Vol 336 ◽  
Author(s):  
M. Zhu ◽  
M.B. Von Der Linden ◽  
W.F. Van Der Weg

ABSTRACTThe low temperature thermally stimulated conductivity (TSC) in a-Si:H film has been investigated in the temperature range from 20 to 150 K. Unlike the results of the high temperature TSC, the low temperature peak value and position (Tm) of TSC do not depend on the starting temperature T0 at low temperatures. This new phenomenon can not be explained by TSC theory [1]. Based on the multiple trapping (MT) Model, TSC theory limits its application to the intermediate and high temperature range. In this paper, a model of the hopping conduction with the transport energy Et in the band tail is proposed to understand the behavior of the low temperature TSC in which the thermal emission energy Em does not depend on the starting temperature of TSC.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 821
Author(s):  
Guangkai Yang ◽  
Changling Zhuang ◽  
Changrong Li ◽  
Fangjie Lan ◽  
Hanjie Yao

In this study, high-temperature tensile tests were carried out on a Gleeble-3500 thermal simulator under a strain rate of ε = 1 × 10−3 s−1 in the temperature range of 600–1310 °C. The hot deformation process of Fe–15.3Mn–0.58C–2.3Al TWIP/TRIP at different temperatures was studied. In the whole tested temperature range, the reduction of area ranged from 47.3 to 89.4% and reached the maximum value of 89.4% at 1275 °C. Assuming that 60% reduction of area is relative ductility trough, the high-temperature ductility trough was from 1275 °C to the melting point temperature, the medium-temperature ductility trough was 1000–1250 °C, and the low-temperature ductility trough was around 600 °C. The phase transformation process of the steel was analyzed by Thermo-Calc thermodynamics software. It was found that ferrite transformation occurred at 646 °C, and the austenite was softened by a small amount of ferrite, resulting in the reduction of thermoplastic and formation of the low-temperature ductility trough. However, the small difference in thermoplasticity in the low-temperature ductility trough was attributed to the small amount of ferrite and the low transformation temperature of ferrite. The tensile fracture at different temperatures was characterized by means of optical microscopy and scanning electron microscopy. It was found that there were Al2O3, AlN, MnO, and MnS(Se) impurities in the fracture. The abnormal points of thermoplasticity showed that the inclusions had a significant effect on the high-temperature mechanical properties. The results of EBSD local orientation difference analysis showed that the temperature range with good plasticity was around 1275 °C. Under large deformation extent, the phase difference in the internal position of the grain was larger than that in the grain boundary. The defect density in the grain was large, and the high dislocation density was the main deformation mechanism in the high-temperature tensile process.


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