Estimation of the α/β region in phase diagrams and mechanical properties with heat treatment temperature in Ti-6242 alloy

Adding Sc to 6xxx series alloys has led to inconsistent results due to the formation of the high-temperature, thermodynamically stable V-phase (AlSc2Si2). Thermo-Calc single-axis equilibrium and phase diagram calculations were employed to identify V-phase formation with varying Si and Zr concentrations, indicating that increasing Zr and decreasing Si lowered the V-phase equilibrium volume fraction. Increasing Zr also shifted the V-phase equilibrium to higher Si concentrations. To access real-world influences of Zr and Si, four compositions were cast with different Si and Zr concentrations: a high-Si, low-Zr alloy; a medium-Si, medium-Zr alloy; a low-Si, high-Zr alloy; and a baseline alloy without Zr and Sc. The compositions were DC-cast followed by multi-step isochronal and isothermal heat treatments, which revealed that increasing Zr concentration did not influence the formation of V-phase but did result in higher hardness at high temperatures, likely due to Al3Zr precipitation. In contrast, higher Si and lower Zr concentrations produced higher hardness in the peak-aged condition but lower hardness at homogenization temperatures in the 400 °C to 520 °C range. Given these conclusions, a new alloy and a multi-step homogenization process are proposed to further develop Sc- and Zr-containing 6xxx extrusion alloys.

In both preparing and using hydrogen-rich reducing gas (H2RG) in direct reduction, carbon deposition occurs if operating parameters are improperly controlled, affecting the entire process. Therefore, a universally applicable method is needed to determine carbon deposition in the CH4-H2-CO-H2O-CO2 system, especially the broader H-C-O system. This study establishes a novel method based on the H-C-O system's mass balance and chemical equilibrium diagram, alongside multi-phase/multi-reaction equilibrium principles. Critical carbon deposition point coordinates (O/C, H/C) were determined under varying conditions including temperatures typically ranging from 550 °C to 900 °C, total pressures from 0.1 to 2.0 MPa, and H2/CO ratios of approximately 2.0-6.9. Connecting points under identical parameters generated critical carbon deposition curves, forming a comprehensive "carbon deposition state diagram for H-C-O system". This diagram allows precise determination of system state and carbon deposition occurrence, providing a theoretical basis for optimizing process parameters to avoid deposition. To overcome complex diagram calculations, specialized analysis software was developed. Validation using experimental and industrial data confirmed the diagram's rationality and practicality. The diagram offers a simple, rapid, and accurate means to predict carbon deposition under specified conditions. Crucially, it guides efforts to prevent deposition while simultaneously minimizing energy consumption and costs in natural gas-based hydrogen production processes. Consequently, the "carbon deposition state diagram for H-C-O system" effectively guides actual production towards cost reduction, lower consumption, stability, and smooth operation.

This study proposes a hybrid experimental-thermodynamic approach to determine the solubility products of rare earth oxysulfides and establish phase equilibria in molten copper. By combining limited experimental data at 1473 K with thermodynamic modeling, we derived temperature-dependent solubility product expressions (1340–1500 K) for Y 2 O 3 , YS, Y 2 O 2 S, Ce 2 O 3 , CeS, and Ce 2 O 2 S. Thermodynamic analysis conclusively rules out the formation of Y 2 S 3 and Ce 2 S 3 . We systematically analyzed the formation criteria for RE 2 O 2 S, RES, and RE 2 O 3 phases in liquid copper and constructed Y/Ce–O–S equilibrium diagrams at 1373 K and 1473 K. These results can provide essential foundational data for copper metallurgy for rare earth additions.

“100 Episodes of Electrolysis (Denkai Hyakuwa)”, written over a span of 13 years by TAKAHASHI Masao and MASUKO Noboru, provides a comprehensive overview of electrochemistry and industrial electrolysis. Published in the bulletin of the Japan Soda Industry Association “Soda & Chlorine”, it consists of about 120 stories including the sequels, covering a broad spectrum from basic concepts to practical applications. The stories explore the development, history, technological advances and challenges of electrochemistry, focusing on key theories such as stoichiometry, equilibrium, mass transfer and kinetics. Practical industry-level examples are used to show how complex problems have been solved in the field. The first two volumes introduce the basics of electrode reactions, while the third volume covers topics such as equilibrium diagrams, electrode potentials and molten salts, including the Monju sodium leak accident. The fourth volume covers advanced technologies related to metal refining, chlorine and caustic soda production, batteries, fuel cells and materials technology. The editor envisions the series of about 120 episodes including the sequels to be a valuable resource for researchers and engineers in electrolysis, as well as those interested in electrochemistry and industrial physical chemistry.

Fenchol- and alpha-terpineol-based eutectic solvents: antimicrobial activities and bixin extraction from annatto mixture

The equilibrium diagram of the Ca–W–Oa–H2O system for the H2C2O4 leaching of scheelite at 298 K was constructed. This diagram clarifies the dominant regions of each component in the system as well as the variation rules of key components with pH value and total concentration of free H2C2O4, thereby confirming the thermodynamic conditions for the H2C2O4 leaching of scheelite. Theoretical analysis results indicate that H2C2O4 can effectively leach scheelite, and the concentration of H2C2O4 is a crucial factor influencing the leaching efficiency. When 1 < pH < 6.4, scheelite reacts with H2C2O4 to form precipitates of H2WO4(s) and CaC2O4(s). Under the condition of maintaining a high concentration of free H2C2O4(aq), H2WO4(s) further reacts with H2C2O4(aq), and the formation of H2[WO3(C2O4·H2O)] with high solubility is predicted, which promotes the leaching of scheelite. When 6.4 < pH < 14.6, the ionization of H2C2O4 is enhanced with the increase of pH, leading to the rise in the concentrations of C2O42− and WO42−. When pH > 14.6, the binding effect between OH− and Ca2+ in the system is sharply strengthened, and CaC2O4(s) is gradually converted into Ca(OH)2(s). Based on the thermodynamic analysis results, experimental verification of H2C2O4 leaching of scheelite was carried out. Under the optimal conditions of H2C2O4 concentration of 2.2 mol L−1, reaction temperature of 80 °C, reaction time of 5 h, liquid-to-solid ratio of 15 : 1, and stirring speed of 100 rpm, the leaching rate of WO3 reached 99.54%, with only 0.53% of WO3 remaining in the leaching residue. Comparison of the XRD, EDS, and FTIR characterization results of raw scheelite and oxalic acid-leached residue reveals that during the leaching process, most of the tungsten enters the leachate in a highly soluble form, while calcium combines with C2O42− to form CaC2O4·H2O precipitate, which is retained in the leaching residue.

ABSTRACT The historical divide between engineering and architecture has perpetuated challenges in reconciling structural and design priorities. Current methods for integrating structure and architecture – form-making and form-finding – each face limitations. Form-making grants designers geometric control but relies on fixed prototypes, restricting formal diversity. Form-finding, though generative, offers minimal intervention post-initiation, limiting design control. Both approaches depend on predefined models (geometric or funicular), constraining innovation. This study proposes a diagrammatic form-finding method using equilibrium prototypes derived from Graphic Statics, which abstractly represent compression-tension relationships. These prototypes act as adaptable starting points for generating diverse structural topologies through geometric and force-based operations, avoiding reliance on fixed models. By maintaining transformable equilibrium diagrams throughout the process, designers gain dynamic control and expanded formal possibilities. The method was tested in undergraduate studios tasked with designing open-air theaters using the computational tool CEM to ensure structural equilibrium. Students produced varied, well-resolved outcomes, demonstrating the approach’s capacity to transcend conventional constraints while balancing creativity and feasibility. The findings suggest that the approach effectively bridges architectural design and structural rationality, offering an educational framework that enhances students’ ability to synthesize novel forms while maintaining structural coherence.

ABSTRACT Current industrial production of ammonium paratungstate via caustic soda and soda decomposition methods faces the challenge on excessive consumption of leaching agent and significant discharge of high-salt wastewater. This paper systematically analyzes the leaching processes of CaWO4 or FeWO4 with NaOH/Na2CO3 solutions through thermodynamic modeling by combining the Pitzer equation and reaction equilibrium constants. Thermodynamic calculation results are in good agreement with the reported data in the literature, verifying its reliability. Thermodynamic equilibrium diagrams of NaOH leaching systems and Na2CO3 leaching systems on scheelite and wolframite are drawn at 298.15–573.15 K. Thermodynamically, the stable zones are CaWO4(s)/FeWO4(s), Na2WO4(aq), and Na2WO4·xH2O(s)/Na2CO3·xH2O(s) during the leaching processes of CaWO4 or FeWO4 with NaOH/Na2CO3 solutions. With the increment of temperature, Na2WO4(aq) stable zone increase in the NaOH leaching systems, while it first increases and then shrinks in Na2CO3 leaching systems. Elevated temperature can decrease the NaOH/Na2CO3 consumption and increase the WO3 concentration during the leaching of CaWO4 and FeWO4 with NaOH/Na2CO3 solutions. Thermodynamic analysis results further explain the suitability of the autoclave method for treating scheelite concentrate while caustic soda decomposition method for treating wolframite concentrate. This research can provide a theoretical basis for near-equilibrium leaching of tungsten mineral raw materials in NaOH and Na2CO3 solutions, which contributes to reducing alkali consumption, high-salt wastewater amount and production cost in tungsten industrial practices.

The use of lithium intercalation electrodes (LIE) for recovering lithium from geothermal sources (containing ≤ 400 ppm of lithium) has the potential to revolutionize the lithium mining industry. This work proposes a conceptual scaled-up process for LIE, utilizing concentrated brine of 15 m3 h−1 (384.32 mM or 2,666 ppm of lithium) obtained from a reverse osmosis unit. Given the high lithium concentration in the concentrated brine, testing LIE performance under high lithium content conditions (1 M LiCl) is essential. In this study, LiMn2O4 supported on vitreous carbon foam is evaluated as the positive electrode. Degradation of the intercalation-active material, LiMn2O4, was observed in acidic media, with significant manganese dissolution. In contrast, at near neutral pH, dissolution rate is considered lower. Faradaic efficiency in acid media showed 98% efficiency only during the first potentiostatic deintercalation run. Subsequent runs exhibited non-faradaic behavior, which was also attributed to manganese dissolution. To develop strategies for mitigating LiMn2O4 degradation, equilibrium diagrams for the Li-Mn-H2O system (Poubaix Diagram) was constructed. In addition to propose a scaled-up process for lithium recovery from geothermal sources, this work investigates the performance of lithium intercalation under conditions relevant to large-scale operations.

Transition metal perovskites and derived compositionshave longbeen suggested as electrocatalysts for the oxygen electrochemicalreactions in alkaline media. This paper presents a study of the alkalinestability of LaBO3 perovskites (B = Co, Ni, Mn, and Fe)by exposing powdered samples to a 2M NaOH solution with pH > 14forvariable periods of time. The elemental analysis of the supernatanttest solution reveals the presence of Fe only after 48 h reactiontime, whereas Co is apparent within the first 12 h. Ni and Mn aredetected after 24 h in quantities like those obtained for Co after12 h. These data suggest that the initial dissolution is primarilydetermined by the nature of the transition metal, in excellent agreementwith calculated Pourbaix equilibrium diagrams. The analysis of thepowders by electron microscopy combined with energy-dispersive spectroscopyand X-ray photoelectron spectroscopy confirms the underlying compositionalchanges, which are particularly important on the surface of the particles,where the transition metal cations tend to be depleted, thereby forminglanthanum-enriched regions. It is concluded from these tests thatthe chemical stability increases in the series Co < Ni < Mn< Fe. A degradation of kinetic parameters for oxygen reductionand evolution reactions (ORR and OER), assessed by linear scanningvoltammetry and time-dependent galvanostatic measurements, is observedwith variable magnitude depending on the transition metal, followingthe same compositional trend of the chemical stability series. Theeffect of the transition metal on ORR and OER performance is wellexplained by the eg orbital occupation model. The dissolutionof these types of materials in strong alkaline media, potentiallyaggravated in compositions where lanthanum is partly substituted byalkaline earths, underlies complex compositional changes that maydetermine the performance and stability of the incorporating device,e.g., fuel cells, metal-air batteries, electrolyzers, or supercapacitors.

Dopamine is commonly used to treat hemodynamic collapse, but its effect on baroreflex-mediated sympathetic arterial pressure (AP) regulation remains to be elucidated. We quantified the effects of dopamine on AP regulation using a baroreflex open-loop analysis by measuring sympathetic nerve activity (SNA) and AP in response to stepwise changes in carotid sinus pressure (CSP) before and during intravenous infusion of dopamine at 2, 10, and 20 µg·kg-1·min-1 in anesthetized rats (n = 8). We analyzed the CSP-SNA relationship (neural arc) and the SNA-AP relationship (peripheral arc) and constructed a baroreflex equilibrium diagram. The gain at the operating point was calculated from the product of the tangential slope of the neural arc and the slope of the peripheral arc. Compared with baseline, dopamine at 20 µg·kg-1·min-1 significantly reduced the maximum gain of the neural arc [from 1.898 ± 0.150 to 1.277 ± 0.205%/mmHg (P = 0.014)]. Compared with baseline, dopamine at 10 and 20 µg·kg-1·min-1 significantly reduced the slope of the peripheral arc [from 0.806 ± 0.079 to 0.645 ± 0.091 mmHg/% (P = 0.031) and 0.633 ± 0.100 mmHg/% (P = 0.020), respectively] and the operating point gain [from 0.800 ± 0.187 to 0.462 ± 0.153 mmHg/mmHg (P = 0.008) and 0.345 ± 0.122 mmHg/mmHg (P < 0.001)] while maintaining the operating point AP. In conclusion, dopamine at 10 and 20 µg·kg-1·min-1 maintained the operating point AP but significantly reduced the operating point gain for AP regulation, potentially increasing AP variability and instability.NEW & NOTEWORTHY Dopamine impaired the arterial pressure (AP) buffering effect mediated by the arterial baroreflex while maintaining AP in anesthetized normal rats. This previously unrecognized effect of dopamine may partially explain why the use of dopamine did not yield favorable outcomes in clinical trials, particularly in patients with shock in whom acute hemodynamic fluctuations can be life-threatening.

This paper proposes a mathematical description of nitriding atmospheres obtained from a one-component ammonia ingoing atmosphere and a two-component ammonia inlet nitrogen-diluted atmosphere. The Fe-N phase equilibrium diagrams of the nitriding atmosphere in the hydrogen content-temperature (Q-T) system for selected NH3/N2 atmosphere compositions are presented. The nitriding atmosphere obtained with different degrees of nitrogen dilution of the ingoing atmosphere was characterized. It has been shown that in processes carried out in nitriding atmospheres obtained from a two-component atmosphere with nitrogen, there is no direct relationship between the value of the nitrogen potential and the degree of dilution of the ingoing atmosphere with nitrogen. It has been shown analytically and confirmed experimentally that with changes in the degree of dilution of ammonia with nitrogen, the hydrogen content of the nitriding atmosphere and, consequently, the nitrogen availability of the nitriding atmosphere change. Using the example of nitriding AISI 52100 steel, it has been experimentally demonstrated that the change in nitrogen availability, caused by a change in the degree of dilution of the ingoing atmosphere with nitrogen, is not accompanied by a change in the value of the nitrogen potential. It has also been shown that the change in the nitrogen availability of the nitriding atmosphere, induced by the change in the composition of the aNH3/bN2 ingoing atmosphere, affects the kinetics of nitrogen mass gain in the nitrided layer and the distribution of nitrogen mass between the iron nitride layer and the solution zone. It has also been shown that with the change in nitrogen availability, what changes in addition to the thickness of the iron nitride layer is also the phase composition of the layer. Using gravimetric tests, the mass of nitrogen in the iron nitride layer and the solution zone has been determined. To describe the equilibrium between the NH3/H2 atmosphere and nitrogen in the different iron phases, a modified Lehrer diagram in the coordinate system of temperature and hydrogen content in the nitriding atmospheres (T-Q) has been proposed.

Hot-dip galvanizing is the most effective method of anti-corrosion protection of steel structures, achieved by the diffusion of zinc into the base steel during immersion in a molten zinc bath. The predictability and sustainability qualities brought by hot dip galvanizing together with the assertion that almost all the con- struction of steel structures that reach the galvanizing sections includes welding joints are emphasized, too. It is shown through the equilibrium diagrams (Fe-C and Fe-Zn) and the annealing graphs the way the working temperature for hot-dip galvanizing process interferes with the stability and mechanical properties of the steel. The existence of variations of zinc layers thicknesses that occur between the base material (the used steel for construction) and the added material used for welding is identified. The relationship between the holding time in the molten zinc bath, the silicon concentration contained in the added welding material and the layers thickness in the welded seam area is graphically presented. As additions, are presented data regarding the importance of proper welding, the adhesion of the zinc layer and the appearance of the surface after galvanizing.

Dopamine is commonly used for treating hemodynamic collapse. However, recent clinical trials have reported that dopamine administration does not necessarily lead to improved patient outcomes, and the underlying reasons remain unclear. Among the mechanisms of autonomic cardiovascular regulation, the arterial baroreflex is one of the most important negative feedback systems for maintaining and stabilizing arterial pressure (AP). The impact of dopamine on baroreflex-mediated sympathetic AP regulation has not been clarified. To test the hypothesis that dopamine affects baroreflex-mediated sympathetic AP regulation, we examined the effects of various doses of dopamine on AP regulation using a baroreflex open-loop analysis. Male Wistar–Kyoto rats were used (n = 8, 14.0 ± 0.6 weeks of age, 367 ± 21 g, mean ± SD). We measured sympathetic nerve activity (SNA) and AP in response to stepwise changes in carotid sinus pressure (CSP), before and during intravenous administration of low-, medium-, and high-dose dopamine (2, 10, and 20 µg·kg−1·min−1, respectively), in anesthetized rats. We analyzed the CSP-SNA relationship (neural arc) and the SNA-AP relationship (peripheral arc) and constructed an equilibrium diagram. The gain at the operating point was calculated from the product of the tangential slope of the neural arc and the slope of the peripheral arc. High-dose dopamine significantly reduced the maximum gain [from 1.898 ± 0.150 to 1.277 ± 0.205 ( P = 0.014) in %/mmHg] and increased the lower limit [from 34.12 ± 6.03 to 56.84 ± 12.40 ( P = 0.017) in %] of the neural arc. Medium- and high-dose dopamine significantly reduced the slope of the peripheral arc [from 0.806 ± 0.079 to 0.645 ± 0.091 ( P = 0.031) and 0.633 ± 0.100 ( P = 0.020) in mmHg/%] and the operating-point gain [from 0.800 ± 0.187 to 0.462 ± 0.153 ( P = 0.008) and 0.345 ± 0.122 ( P &lt; 0.001) in mmHg/mmHg] compared to baseline, while maintaining the operating-point AP [from 94.5 ± 2.9 to 87.8 ± 4.1 (not significant) and 87.7 ± 4.5 (not significant) in mmHg]. In conclusion, medium- and high-dose dopamine maintained the operating-point AP but significantly reduced the operating-point gain for the AP regulation, potentially increasing AP variability and instability. These results may help understand why the use of dopamine did not yield favorable outcomes in past clinical trials, particularly in patients with shock where acute hemodynamic fluctuations can be life-threatening. This work was supported by the Grant-in-Aid for Scientific Research (24K23423) and the research grant from NTT Research, Inc. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

The interaction of the components in the Y–Dy–Ge ternary system was investigated using the methods of X-ray phase analysis, microstructure and energy dispersive X-ray spectroscopy in the whole concentration range at temperature of 870 K. The existence of continuous solid solutions of substitution with the AlB2 (Y1-xDyxGe1.5), Y3Ge5 (Y3-xDyxGe5), CrB (Y1-xDyxGe), Ho11Ge10 (Y11-xDyxGe10), Sm5Ge4 (Y5-xDyxGe4) and Mn5Si3 (Y5-xDyxGe3) structure types was found. Limited solid solutions of the substitution type, based on the binary compounds YGe1,82 (0.20 at. part Dy), YGe2 (~ 0,10 at. part Dy), DyGe1,9 (0.07 at. part Y) and DyGe1,85 (0.05 at. part Y) were observed. The electrical and magnetic properties of the Y5Dy30Ge65 (DyGe1,85 structure type) and (YGe1,82 structure type) alloys were studied. The phase Y30Dy5Ge65 is Curie-Weiss paramagnet in the investigated temperature range. On the thermogram of the Y10Dy20Ge65 alloy during cooling, we observe an intense peak at temperature of 1207.4 K (at maximum), the thermal effect of which reflects the formation of the Dy1-xYxGe1.85 phase.

Evidence suggests that brain insulin availability acutely modulates arterial baroreflex function. However, little is known about the impact of blocking brain insulin receptor (IR) signaling on arterial baroreflex. We hypothesized that blockade of IR signaling in the brain acutely impairs arterial baroreflex function. Our hypothesis was tested using baroreflex open-loop analysis to evaluate the two subsystems of the arterial baroreflex: the carotid sinus pressure (CSP)-sympathetic nerve activity (SNA) relationship (the neural arc) and the SNA-arterial pressure (AP) relationship (the peripheral arc). In anesthetized healthy male rats, the bilateral carotid sinus baroreceptor regions were surgically isolated from the systemic circulation, and then CSP was changed stepwise from 60 to 180 mmHg before and over 120 min after lateral intracerebroventricular (ICV) administration of either artificial cerebrospinal fluid (control solution) or IR antagonist GSK1838705. ICV injection of GSK1838705 significantly decreased renal SNA (RSNA), AP, and heart rate during stepwise CSP input over a period of 120 min after administration (p < .05). The maximum gain of the neural arc was significantly reduced 120 min after ICV injection of GSK1838705 (p = .002). Furthermore, GSK1838705 significantly attenuated the operating-point RSNA (p = .025) and AP (p < .001) as estimated by the baroreflex equilibrium diagram. Moreover, 120-min baroreflex stimulation via stepwise CSP input significantly increased c-Fos expression in IR-positive neurons in medullary cardiovascular centers (p < .001). Our findings suggest that IR signaling in the brain can modulate AP regulation via alteration of the neural arc of the arterial baroreflex.

The study is devoted to the numerical modeling of diffusion processes in aluminum-copper bimetals using the finite element method. The focus is on the peculiarities of interdiffusion during the heat treatment of Al–Cu bimetallic materials and on the processes of formation and growth of intermetallic compounds in the Al–Cu system under elevated temperatures. The application of a migration diffusion model made it possible to account for the influence of temperature and stress concentration on the annealing process and on the interaction of materials and compounds under heating – an aspect unattainable with the standard diffusion model. This approach also enabled the construction of concentration distribution curves for copper and aluminum at different annealing temperatures and durations. A computational algorithm was developed for the formation and growth of intermetallic compounds in the sample, taking into account annealing temperature and the concentration of diffusing elements in accordance with the Al–Cu phase equilibrium diagram. As a result, intermetallic layers forming at the metal–metal interface during interdiffusion of copper and aluminum were obtained, which is consistent with experimental findings. It is shown that the numerical experiment demonstrates good qualitative and quantitative agreement with experimental data on the thickness of the diffusion layer at the Al–Cu interface, with the simulated phase dimensions matching those observed experimentally within the margin of error.

This paper presents the results of an experimental study on the phase equilibrium diagram of the binary system “Freon R404A–acetone” at a temperature of T = 356 K. These results are crucial for selecting optimal thermodynamic conditions for the supercritical fluid extraction of acetone from aqueous solutions using R404A freon as an extractant. This process is particularly relevant for addressing wastewater disposal challenges at the Bisphenol-A production facility at PJSC Kazanorgsintez (Russian Federation), which manufactures phenol and acetone. The studied binary mixture exhibits type I–II phase behavior, characterized by the termination of the two-phase “liquid–vapor” equilibrium at critical points corresponding to various temperatures, a continuous critical curve, and a gas-phase region of complete miscibility beyond the binodal. The ability to approach the critical point-where the mixture displays anomalous changes in properties- may significantly enhance the efficiency of the supercritical fluid extraction process compared to systems exhibiting type V phase behavior. At the studied temperature, the critical pressure was determined to be Pkр = 4.14 MPa.

The vibrational dynamics and phase behavior of deep eutectic systems (DES) comprising ammonium salts and urea have been investigated using a combination of computational chemistry with inelastic neutron scattering (INS) and isotopic substitution. The study explores the impact of cation (a)symmetry on the vibrational modes of ammonium salts and urea in eutectic mixtures. By employing deuterated urea in tetraalkylammonium-based DES mixtures, selective observation of the INS spectra of individual components is achieved. Subtracting INS spectra for isotopically substituted urea mixtures provided separate "views" of the salt and urea contributions, highlighting changes in intermolecular interactions. Two types of organization of urea molecules are derived from the INS bands of urea in the mixture with symmetric and asymmetric cations. This is consistent with the view that the cation's asymmetry affects mostly the urea side of the solid-liquid equilibrium diagram and deep eutectic behavior stems from the deviation of the urea solid-liquid equilibrium line from ideality.