Temperature Phase Research Articles

Use of Frit‐Disc Crucible Sets to Make Solution Growth More Quantitative and Versatile

The recent availability of step‐edge, frit‐disc crucible sets (generally sold as Canfield Crucible Sets or CCS) has led to multiple innovations associated with the group's use of solution growth. The use of CCS allows for the clean separation of liquid from solid phases during the growth process. This clean separation enables the reuse of the decanted liquid, either allowing for simple, economic, savings associated with recycling expensive precursor elements or allowing for the fractionation of a growth into multiple, small steps, revealing the progression of multiple solidifications. Clean separation of liquid from solid phases also allows for the determination of the liquidus line (or surface) and the creation, or correction, of composition–temperature phase diagrams. The reuse of clean decanted liquid has also allowed to prepare liquids ideally suited for the growth of large single crystals of specific phases by tuning the composition of the melt to the optimal composition for growth of the desired phase, often with reduced nucleation sites. Finally, it is discussed how solution growth and CCS use can be harnessed to provide a plethora of composition–temperature data points defining liquidus lines or surfaces with differing degrees of precision to either test or anchor artificial intelligence and/or machine‐learning‐based attempts to augment and extend the limited experimentally determined database.

Magnetic structure of Mn2GaC thin film by neutron scattering

Abstract MAX phases are a family of atomically laminated materials with various potential applications. Mn2GaC is a prototype magnetic MAX phase, where complex magnetic behaviour arises due to competing interactions. We have resolved the room temperature magnetic structure of Mn2GaC by neutron diffraction from single-crystal thin films and we propose a magnetic model for the low temperature phase. It orders in a helical structure, with a rotation angle that changes gradually between 120° and 90° depending on temperature.

Accurate prediction of thermoresponsive phase behavior of disordered proteins.

Protein responses to environmental stress, particularly temperature fluctuations, have long been a subject of investigation, with a focus on how proteins maintain homeostasis and exhibit thermoresponsive properties. While UCST-type (upper critical solution temperature) phase behavior has been studied extensively and can now be predicted reliably using computational models, LCST-type (lower critical solution temperature) phase transitions remain less explored, with a lack of computational models capable of accurate prediction. This gap limits our ability to probe fully how proteins undergo phase transitions in response to temperature changes. Here, we introduce Mpipi-T, a residue-level coarse-grained model designed to predict LCST-type phase behavior of proteins. Parametrized using both atomistic simulations and experimental data, Mpipi-T accounts for entropically driven protein phase separation that occurs upon heating. Accordingly, Mpipi-T predicts temperature-driven protein behavior quantitatively in both single- and multi-chain systems. Beyond its predictive capabilities, we demonstrate that Mpipi-T provides a framework for uncovering the molecular mechanisms underlying heat stress responses, offering new insights into how proteins sense and adapt to thermal changes in biological systems.

Separation of deaminated impurities from the desired oligonucleotides using supercritical fluid chromatography.

With recent advancements concerning the optimization of the analytical conditions, it is feasible to analyze polar molecules using supercritical fluid chromatography (SFC). In this study, the applicability of SFC is evaluated for analyzing 5-, 10-, 15-, and 18-mer oligonucleotides, and SFC is then applied to analyze deaminated products, which are side products generated during oligonucleotide synthesis. These side products are difficult to separate from the target oligonucleotide, with the difficulty varying depending on the deamination position and sequences, even when using ion-pair reversed-phase liquid chromatography (IP-RPLC), a common method for oligonucleotide analysis. Our results demonstrate that SFC, with octylamine as a modifier additive, can achieve sharp chromatographic peaks for 5-, 10-, 15-, and 18-mer oligonucleotides modified with 2'-O-methoxyethyl RNA (2'-MOE), regardless of the presence of the hydrophobic 4,4'-dimethoxytrityl (DMTr) group on the sequence. After optimization of the column oven temperature, modifier additive, and stationary phase, SFC successfully separated oligonucleotides with various numbers and positions of deamination from the target oligonucleotide. SFC exhibited different selectivities for DMTr-on and DMTr-off oligonucleotides compared with those for IP-RPLC, which indicates that SFC can serve as a valuable alternative tool for the purification and analysis of oligonucleotides.

Composition evolution of crystal structure and negative thermal expansion in pyro-vanadate–phosphate Cu1.8Zn0.2V2–xPxO7

We constructed a composition–temperature phase diagram for Cu1.8Zn0.2V2–xPxO7 based on structural analysis conducted using synchrotron radiation over the entire compositional range and a wide temperature (110–760 K) range. As x increases, the structure changes from the β-Cu2V2O7 structure (C2/c) to the α-Cu2P2O7 structure (C2/c), and then to the β-Cu2P2O7 structure (C2/m). Accordingly, the crystallographic negative thermal expansion (NTE) weakens, especially in the β-Cu2P2O7 structure, but it never disappears completely. We also discovered that for x = 0.75–1.0, a phase transition occurs from the α-Cu2P2O7 structure to the β-Cu2P2O7 structure with increasing temperature, accompanied by large volume contraction of at most 1.5%. The anisotropic thermal deformation of the unit cell, which indicates the effectiveness of the microstructural effects enhancing the NTE, also weakens as x increases. Elucidation of NTE requires discussion beyond the crystal structure alone, such as local structure related to the soft linkage between polyhedra.

Micro-encapsulation of Si-Fe ultra-high temperature phase change material: Fabrication and basic energy storage properties

Micro-encapsulation of Si-Fe ultra-high temperature phase change material: Fabrication and basic energy storage properties

Stability Analysis of a Multicomponent Vapor-Gas Bubble in Contact with a Liquid-Gas Solution.

Stability of vapor-gas bubbles, homogeneously nucleated within a liquid-gas solution, depends on the temperature and pressure of the liquid phase, along with the concentration of dissolved gaseous components. While extensive theoretical and experimental investigations have been conducted on bubble nucleation within single-component systems, research on multicomponent systems has mainly focused on binary liquid-gas solutions comprising a solvent and one dissolved gas. Moreover, existing studies on the stability of vapor-gas bubbles have predominantly examined the stability with respect to bubble size, leaving other critical factors relatively unexplored. Here, we present a methodology to determine potential equilibrium states for a single vapor-gas bubble homogeneously nucleated within a large multicomponent liquid-gas solution, encompassing a subcritical solvent and n - 1 gaseous components, with temperature and liquid phase pressure held constant. Additionally, we assess equilibrium state stability by analyzing the free energy change of the system with respect to both bubble size and the composition of the vapor-gas phase within the bubble, using rigorous phase equilibrium equations to account for nonideal behavior in both liquid-gas and vapor-gas phases. We then apply this to investigate the number and nature of equilibrium states in a ternary system of water-oxygen-nitrogen across various scenarios of oxygen and nitrogen saturation levels in the liquid phase, while also meticulously examining the effects of liquid phase temperature and pressure on the stability of the system. The proposed model can be used to optimize the design of micro-nano bubble technologies for diverse engineering applications, ranging from agriculture to water treatment and biomedicine.

Open Electrochemical Liquid Phase Epitaxial Growth of Crystalline Ge Films.

Room temperature and ambient pressure electrochemical liquid phase epitaxy (ec-LPE) of macroscopic Ge(100) films using uncompressed liquid metal electrodes has been achieved. Experiments were performed in aqueous electrolytes containing dissolved GeO2 and Na2B4O7 using Hg, Hg0.35In0.65, Ga, or Ga0.83In0.17 (e-GaIn) working electrodes. The resultant crystalline Ge films were characterized via scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and selected area electron diffraction. e-GaIn was identified as the liquid metal composition that produced the most uniform and largest area Ge epi-films. Thickness profiles of the electrodeposited Ge films showed thicknesses that decreased at distances further from the three-phase boundary between the liquid metal, aqueous electrolyte, and solid seed substrate, consistent with the premise that In specifically facilitates nucleation and crystal growth via surface diffusion. This study thus establishes "open" ec-LPE as a method to synthesize single crystalline semiconductors and makes recommendations for improving the prospects of "open" ec-LPE based on the cumulative observations presented herein.

Cubic calcite and its structural phase transitions

Calcite, CaCO3, has been reported to exist in as many as seven different structural forms. The structure at room temperature and pressure (space group R3¯c, ‘Phase I’) was established by Bragg many years ago. A phase transition to a higher temperature phase (space group R3¯m, ‘Phase V’) was noted to occur at around 1240 K—this may proceed via an intermediate phase (space group again R3¯c, referred to as ‘Phase IV’). These phases differ primarily in the disposition of the CO3 groups. Additional phases are found at higher pressures. We report a para-phase (parent phase, virtual prototype, aristotype) which assists in understanding the different phases, the phase transitions, and especially the domain structures and twin wall boundaries associated with these transitions. Molecular dynamics methods were used to study the temperature evolution of an isothermal-isobaric (NPT) ensemble of some 384,000 atoms. These computations reproduced the features of the known structures in R3¯c and R3¯m and then, at higher temperature, revealed a structure of the sodium chloride type (space group Fm3¯m) in which the entities were the Ca2+ cation and the CO32− anion, this latter with effectively spherical symmetry. On this basis we have upon cooling a necessarily first order ferroelastic transition from cubic Fm3¯m to rhombohedral R3¯m, computed to occur at a simulated temperature of 1900 K, and a possibly continuous transition from the R3¯m to rhombohedral (on a doubled cell) R3¯c computed to occur at about 1525 K. The computations also allowed us to follow the domain structure and twin walls as a function of temperature, during both heating and cooling. The structure just below the R3¯m to R3¯c transition shows strong disorder in the orientation of the CO3 groups, and this may be what is sometimes referred to as Phase IV. The domain structure just below the cubic to rhombohedral transition shows twinning of typical ferroelastic character. The doubling of the cell below the R3¯m to rhombohedral (on a doubled cell) R3¯c leads to a more complicated twin pattern. Indeed, the different structures can be identified from patterns of twinning. Differences between domain structures obtained on heating and cooling indicate extensive thermal metastabilities.

Reference Correlation of the Thermal Conductivity of Nitrogen from the Triple Point to High Temperatures and Pressures

A new wide-ranging correlation for the thermal conductivity of nitrogen, based on the most recent ab initio dilute gas theoretical calculations, a simplified crossover critical enhancement contribution, and critically evaluated experimental data, is presented. The correlation is designed to be used with a high-accuracy Helmholtz equation of state over the range of temperatures from the triple-point temperature to 1000 K, and at pressures up to 2200 MPa. The estimated expanded uncertainty (at the 95 % confidence level) in the range of validity of the correlation ranges from a minimum of 1 % in the gas phase for temperatures from 102 K to 700 K at pressures up to 1 MPa, to 4 % in the high temperature, high pressure region covering 500 K < T < 744 K at pressures from 1 MPa to 40 MPa. In the gas and supercritical region 112 K < T < 475 K for pressures 1 MPa < p < 1000 MPa the estimated uncertainty is 2.2 %, and for the liquid from 81 K to 122 K at pressures up to 70 MPa the estimated uncertainty is 3 %. The correlation behaves in a physically reasonable manner when extrapolated to temperatures below the triple point and is suitable for use in certain corresponding-states applications. However, care should be taken when using the correlation outside of the experimentally validated range.

Effect of water on asphaltene-precipitation behavior of CO2-crude oil mixtures during CCUS processes

Effect of water on asphaltene-precipitation behavior of CO2-crude oil mixtures during CCUS processes

LCST‐UCST Hybrid Phase Diagram of Poly(ɛ‐Caprolactone)/Poly(Styrene‐co‐Acrylonitrile) Blends Through Thermal and Rheological Approaches: Effects of PCL Molecular Weight and Cooling Ramp Rate

ABSTRACTThe lower critical solution temperature (LCST) phase diagram of poly(ɛ‐caprolactone)/poly(styrene‐co‐acrylonitrile) (PCL/SAN) blend was obtained through temperature sweep rheological tests. The effect of the cooling rate of the temperature sweep test and the increased molecular weight of PCL on the phase separation points of PCL/SAN blends was studied. The phase transition boundary of PCL/SAN blends was investigated using the changes in the slope of the storage modulus curve in terms of temperature as well as the spinodal temperatures based on Ajji and Choplin's theory. The LCST diagram obtained through the temperature sweep test for PCL/SAN blends moved to higher points with the increase in the molecular weight of PCL, and the phase diagram was moved to lower points by increasing the cooling rate of the temperature sweep tests. With the increase in the molecular weight of faster PCL phase in the blend, the viscoelastic difference of the two phases decreased and the compatibility window expanded.

High temperature phase transformation of natural zeolites for cesium sequestration: insight into stilbite and heulandite

High temperature phase transformation of natural zeolites for cesium sequestration: insight into stilbite and heulandite

Broken Symmetry and Elastic Frustration in Isostructural MnIII Spin Crossover Crystals.

Symmetry breaking spin state transitions in two of three isostructural salts of MnIII spin crossover cations, [MnIII(3-OMe-5-NO2-sal2323)]+, with heavy anions are reported. The ReO4 - (1) salt undergoes two-step spin crossover which is coupled with a re-entrant symmetry breaking structural phase transition between a high temperature phase (S=2, C2/c), an intermediate ordered phase (S=1/S=2, P21/c), and a low temperature phase (S=1, C2/c). The AsF6 - (2) complex undergoes an abrupt transition between a high temperature phase (S=2, C2/c) and a low temperature ordered phase (S=1/S=2, P ). The SbF6 - (3) complex undergoes a gradual transition between a high temperature phase (S=2, P ) and a low temperature spin state ordered phase (S=1/S=2, P- ). Correlation of the volume of the anion and the T1/2 of the transitions in these complexes and three analogous complexes with similar anions, BF4 - (4), ClO4 - (5), PF6 - (6), reveals an increase in T1/2 upon increasing the anion volume. We rationalise that the volume of the anions used modulates the elastic interactions between the MnIII sites in the lattice, with increasing elastic frustration with the larger anions resulting in a two-stepped transition for 1 and the stabilisation of the mixed (HS:LS) state to low temperature for 2 and 3.

Pressure and temperature response and phase transition path during small hole leakage in a near-industrial scale CO2 pipe

ABSTRACT As a large-scale CO2 migration method, pipelines play a crucial role in the CCUS industry chain. Small hole leakage caused by self defects, fatigue and corrosion, and natural disasters is a common accident in CO2 pipelines. When leaked CO2 is sprayed out through a small hole, the temperature inside the pipeline drops sharply under the Joule Thomson effect. This sudden temperature drop significantly reduces the toughness of the material, increases the risk of brittle fracture. In order to improve the CO2 pipeline release database, a new industrial scale CO2 pipeline has been built. The CO2 release experiments were carried out by using this experimental device. The experimental results showed that the pressure drop rate was fast under high pressure and then slowed down when the pressure dropped below the critical pressure, with the coexistence of gas and liquid. Rapid pressure drop and slight rebound occur during the leakage process, and low initial pressure leads to a more pronounced pressure plateau effect. Dense-phase CO2 leakage produced more dry ice than supercritical state, and the far field sublimation effect was more significant. In practice, particular attention should be paid to safety far from the leakage end.

The phase diagram and strengthening behavior of compositionally complex carbides under high pressure

AbstractThe application of compositionally complex carbides under extreme conditions has garnered significant attention. The phase diagram compositionally complex transition metal carbide (Ta0.2Nb0.2Hf0.2Zr0.2V0.2)C for synthesis under high‐pressure and high‐temperature has been systematically investigated for the first time, and a pressure‐induced decrease in the compositionally complex carbides phase formation temperature was observed. The asymptotic Vickers hardness and bulk modulus of (Ta0.2Nb0.2Hf0.2Zr0.2V0.2)C reached 24.0 GPa and 311.3 GPa. The bulk modulus demonstrates an approximate 30% improvement compared to the average values of individual carbides, indicating that it possesses relatively competitive mechanical properties within the compositionally complex carbides group. The Claperon equation has been utilized to predict the lattice contraction of compositionally complex carbides during phase formation, and the physical mechanism of the high‐pressure strengthening has been proposed accordingly. In summary, the research of pressure–temperature phase diagram and the high‐pressure strengthening mechanism lay a valuable theoretical basis for the structural design and performance optimization of novel compositionally complex carbides.

Application of Finite Volume Method Based on the C-N Format with Parallel Algorithms in Metal Thermal Phase Transition Coupled Field

The numerical simulation of metal heat treatment is of great significance for the development of new materials or processes. The complex coupling relationship in metal heat treatment poses a huge challenge to the overall solution. A finite volume method based on the Crack–Nicolson (C-N) scheme with parallel algorithms is proposed for solving the coupling of metal thermal phase transition. Taking the quenching simulation problem of bearing rings as an example, the calculation accuracy and speed of this method were evaluated by comparing the results of the temperature field and phase transformation field obtained from the literature. In addition, grid independence analysis was conducted to demonstrate the rationality of the established model. The finite volume method using a hexahedral mesh C-N format improves the accuracy of calculations. Optimizing the equation form and using parallel algorithms have improved computational speed. In the trial example, in the 850 °C quenching simulation of GCr15, the outer ring of the bearing is composed of 89.1% martensite and 10.9% residual austenite. The results compare with test verification, which shows that the model performs well in the numerical simulation of metal heat treatment.

Weather-Related Factors and Patient-Reported Outcomes (PROs) in Cancer Patients: Results from the ExPRO Study

Objective The ExPRO (External factors influencing patient reported outcomes of patients with malignant diseases) study explored associations between QoL data and environmental factors on the day of questionnaire completion: mean temperature, sunshine hours, season, and lunar phase. Methods We undertook a cross-sectional analysis of baseline data in the prospective cohort study at two cancer centers in eastern Germany. From December 2020 to December 2021, cancer patients completed the EORTC QLQ-C30 questionnaire upon admission. Statistical analysis was performed to explore associations between QoL data and environmental factors, including temperature, sunshine hours, season, and lunar phases. Results We received 5040 responses (54% male). QoL scores were highest at 25-30 °C and lowest at 5-10 °C (mean 61.3 vs. 52.6, p <0.001). Insomnia was highest at ≤0 °C and lowest at 25-30 °C (mean 39.3 vs. 29.5, p <0.001). QoL was highest with 8 hours of sunshine and lowest with 0 hours (mean 56.9 vs. 50.9, p = 0.003). Conclusion Higher temperatures, more sunshine, and summer seasons are associated with higher QoL in cancer patients, while lower temperatures and reduced sunlight are associated with poorer QoL. These findings highlight the need to consider environmental factors in PRO assessments.

Shifting Patterns of Ethiopian MAM Rainfall: Effects of Sea Surface Temperature and Atmospheric Circulation (1981–2022)

ABSTRACTUnderstanding seasonal rainfall patterns and variability is crucial for managing water resources, pastoral and agricultural activities in Ethiopia, an especially climate‐vulnerable country. This study examines trends in March–April–May (MAM) rainfall from 1981 to 2022, emphasising the relationships between climate indices, atmospheric circulation patterns, and variations in precipitation. By utilising daily CHIRPS rainfall data and monthly sea surface temperature (SST), sea level pressure (SLP) and other reanalysis datasets, we applied extreme indices analysis, correlation analysis and Student's t‐tests to compare climate factors and rainfall during two distinct periods 1(981–2001 and 2002–2022) and assess changes relative to the 1991–2020 long‐term mean. Our findings reveal a notable shift towards warmer sea surface temperature (SST) phases in key ocean basins, with significant positive correlations (r &gt; 0.45, p &lt; 0.05) between Ethiopian MAM rainfall and SSTs in the Mediterranean, Northwest Pacific, Northern Atlantic and Western Indian Ocean. Precipitation patterns shifted from above‐average to below‐average rainfall, aligning with opposite trends in the tropical central Indian Ocean. A long‐term trend analysis revealed a marked decrease in rainy days across northeast, east, central, south and southeastern Ethiopia during 2002–2022, with an increase in consecutive dry days and a decrease in consecutive wet days, with statistical significance at the 95% confidence level. The period from 2002 to 2022 was characterised by La Niña‐like conditions and a negative Pacific Decadal Oscillation, which had a considerable impact on rainfall patterns. Changes in large‐scale atmospheric circulation reduced moisture transport to Ethiopia, leading to drier conditions. These findings enhance our understanding of Ethiopian rainfall variability and its drivers, crucial for improving early warning systems and developing climate adaptation strategies in the region.

Thermodynamic insights into the Ba–S system for the formation of BaZrS3 perovskites and other Ba sulfides

Pressure–temperature phase diagram for the Ba–S system.