scholarly journals Estimation of the Critical Temperatures of Some More Deep Eutectic Solvents from Their Surface Tensions

2018 ◽  
Vol 2018 ◽  
pp. 1-3 ◽  
Author(s):  
Yizhak Marcus

The critical temperatures of two dozen deep eutectic solvents, for only some of which these have been estimated previously, were estimated from the temperature dependences of their surface tensions and densities available in the literature according to the Eötvös and the Guggenheim expressions.

1989 ◽  
Vol 4 (5) ◽  
pp. 1140-1142 ◽  
Author(s):  
L. Anthony ◽  
B. Fultz

Rapidly quenched powders of Fe3Al were subjected to thermal annealings at temperatures well below the critical temperatures for B2 and DO3 ordering. X-ray diffractometry was used to measure the subsequent evolution of B2 and DO3 long-range order. It was found that the relative rates of change of B2 and DO3 order parameters were temperature dependent; hence at different temperatures the alloy passed through different states of order en route to thermal equilibrium. These temperature dependences of “kinetic paths” can be understood in terms of a theory of kinetic paths based on the kinetic master equation. The theory indicates that the temperature dependence of the observed kinetic paths originates from having first-nearest-neighbor interactions that are stronger than second-nearest-neighbor interactions. This seems consistent with previous thermodynamic analyses of critical temperatures of Fe3Al.


2021 ◽  
Vol 342 ◽  
pp. 117445
Author(s):  
Reza Haghbakhsh ◽  
Mehrdad Taherzadeh ◽  
Ana Rita C. Duarte ◽  
Sona Raeissi

2020 ◽  
Vol 307 ◽  
pp. 112972
Author(s):  
Reza Haghbakhsh ◽  
Mehrdad Taherzadeh ◽  
Ana Rita C. Duarte ◽  
Sona Raeissi

2019 ◽  
Vol 62 (3) ◽  
pp. 222-227
Author(s):  
A. G. Тyagunov ◽  
Е. Е. Baryshev ◽  
G. V. Tyagunov ◽  
Т. K. Кostina ◽  
K. Yu. Shmakova

At present time, metallurgical wastes are used in metallurgical alloys production more and more. The volume accumulation and increase of return age effect on charge pollution by undesirable elements and nonmetallic inclusions. As a result, structure and properties of the casting inevitably get worse. This circumstance must influence on polytherm’s character of physical properties of the melt, necessary temperature and time parameters of the heat-resistant alloy’s melting accordingly. We have researched the temperature dependences of electrical resistance and kinematic viscosity of liquid heat-resistant composites based оn Ni – Nb – Cr – Mo systems. The critical temperatures were determined for the EP902 alloy. Heating up to these temperatures leads to irreversible changes in direction of the melt improving. Interaction was found between the amount of foundry waste and features of temperature dependences of the melt physico-chemical properties. An increase in the amount of foundry waste using in remelting results in the critical temperatures increasing. Influence of the melt conditions on crystallization process and on the structure of hard metal has been studied. The process of alloy EР902 solidification was researched by differential thermal analysis method. It has shown that the crystallization process starts with extraction of solid solution on the base of γ-phases and ends with forming of the eutectic based on the Ni3Nb intermetallic compound. Heating of the melt over the critical temperature leads to an increase of supercooling and does not effect on the eutectic temperature. The processing mode of the high temperature melt treatment was proposed based on the research results of physico-chemical properties of the liquid metal and process of the melt crystallization. It allows obtaining the highest quality of casting of heat-resistant EР902 alloy, which contains significant amount of foundry waste in the charge. The mechanical tests were implemented for experimental samples melted out by the optimal mode of high-temperature melt treatment (HTTM). Application of HTTM for the melts, contained 50 % of foundry waste in charge, allows obtaining the level of strength and plastic properties exceeding the technical requirements, stabilizing and combining it from melt to melt.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reza Haghbakhsh ◽  
Sona Raeissi ◽  
Ana Rita C. Duarte

AbstractThe urgency of advancing green chemistry from labs and computers into the industries is well-known. The Deep Eutectic Solvents (DESs) are a promising category of novel green solvents which simultaneously have the best advantages of liquids and solids. Furthermore, they can be designed or engineered to have the characteristics desired for a given application. However, since they are rather new, there are no general models available to predict the properties of DESs without requiring other properties as input. This is particularly a setback when screening is required for feasibility studies, since a vast number of DESs are envisioned. For the first time, this study presents five group contribution (GC) and five atomic contribution (AC) models for densities, refractive indices, heat capacities, speeds of sound, and surface tensions of DESs. The models, developed using the most up-to-date databank of various types of DESs, simply decompose the molecular structure into a number of predefined groups or atoms. The resulting AARD% of densities, refractive indices, heat capacities, speeds of sound and surface tensions were, respectively, 1.44, 0.37, 3.26, 1.62, and 7.59% for the GC models, and 2.49, 1.03, 9.93, 4.52 and 7.80% for the AC models. Perhaps, even more importantly for designer solvents, is the predictive capability of the models, which was also shown to be highly reliable. Accordingly, very simple, yet highly accurate models are provided that are global for DESs and needless of any physical property information, making them useful predictive tools for a category of green solvents, which is only starting to show its potentials in green technology.


Author(s):  
C.A. Baechler ◽  
W. C. Pitchford ◽  
J. M. Riddle ◽  
C.B. Boyd ◽  
H. Kanagawa ◽  
...  

Preservation of the topographic ultrastructure of soft biological tissues for examination by scanning electron microscopy has been accomplished in the past by using lengthy epoxy infiltration techniques, or dehydration in ethanol or acetone followed by air drying. Since the former technique requires several days of preparation and the latter technique subjects the tissues to great stress during the phase change encountered during air-drying, an alternate rapid, economical, and reliable method of surface structure preservation was developed. Turnbill and Philpott had used a fluorocarbon for the critical point drying of soft tissues and indicated the advantages of working with fluids having both moderately low critical pressures as well as low critical temperatures. Freon-116 (duPont) which has a critical temperature of 19. 7 C and a critical pressure of 432 psi was used in this study.


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