Thermophysical Properties of FUNaK (NaF-KF-UF4) Eutectics.

General interest in the deployment of molten salt reactors (MSRs) is growing, while the available data on uranium-containing fuel salt candidates remains scarce. Thermophysical data are one of the key parameters for reactor design and understanding reactor operability. Hence, filling in the gap of the missing data is crucial to allow for the advancement of MSRs. This study provides novel data for two eutectic compositions within the NaF-KF-UF4 ternary system which serve as potential fuel candidates for MSRs. Experimental measurements include their melting point, density, fusion enthalpy, and vapor pressure. Additionally, their boiling point was extrapolated from the vapor pressure data, which were, at the same time, used to determine the enthalpy of vaporization. The obtained thermodynamic values were compared with available data from the literature but also with results from thermochemical equilibrium calculations using the JRCMSD database, finding a good correlation, which thus contributed to database validation. Preliminary thoughts on fluoride salt reactor operability based on the obtained results are discussed in this study.

Chlorine-induced Gas-Solid coupled corrosion behaviors of tube materials in high steam parameter MSW incinerator.

The fast development of the waste incineration industry requires deeper insights into heating surface corrosion behavior at higher operating parameters with complex corrosion sources. This research investigates the corrosion behaviors of three types of plates, namely SA210-C, TP310, and 12CrMoV, when subjected to simulated flue gas and fly ash deposition simultaneously at temperatures ranging from 500℃ to 620℃. The results indicate that the weight loss due to coupling corrosion was 2.5 to 84.5 times higher than that of gas-phase corrosion under the same operating conditions. Among the three stainless-steels, TP310 demonstrates superior corrosion resistance. It is worth noting that, under the gas-solid coupling corrosion conditions, we observed a distinct two-layer structure of corrosion products. Despite the fly ash simulants detaching over time, the two-layer structure remained unchanged. Based on the theory of eutectic molten salt formation, we propose that alkali metal chlorides only initiate the formation of the molten layer in the initial stage of corrosion. Furthermore, we offer additional suggestions for the mechanism of sustaining the molten layer in the absence of alkali metal chlorides.

Muscle biopsy long-chain omega-3 polyunsaturated fatty acid compositions, IMF and FMP in Australian pasture-based Bowen Genetics Forest Pastoral Angus, Hereford, and Wagyu Beef Cattle.

BACKGROUND: We investigated breed and gender variations in the compositions of long-chain (≥ C20) omega-3 polyunsaturated fatty acids (LC omega-3 PUFA), fat melting point (FMP) and intramuscular fat (IMF) contents in biopsy samples of the M. longissimus dorsi muscle of grazing beef cattle. The hypothesis that biopsy compositions of health-beneficial LC omega-3 PUFA, FMP and IMF in a pasture-based production system will vary with breed, was tested. Muscle biopsies were taken from 127 yearling pasture-based Angus, Hereford, and Wagyu heifers and young bulls exclusive to the Australian Bowen Genetics Forest Pastoral breeding stud averaging 12 ± 2.43 months of age and under the same management routine. RESULTS: Breed had a significant influence on IMF, FMP, and the compositions of oleic acid, α-linolenic acid (ALA), eicosapentaenoic (EPA), docosahexaenoic (DHA), docosapentaenoic (DPA), and total EPA + DHA + DPA in the M. longissimus dorsi muscle biopsies (P ≤ 0.03). The Wagyu breed had the highest (11.1%) and Hereford the lowest (5.9%) IMF (P = 0.03). The reverse trend was observed in FMP values where the Hereford breed had the highest (55 °C), Angus intermediate (46.5 °C), and Wagyu the lowest (33 °C) FMP. The Wagyu and Angus breeds had similar oleic fatty acid (18:1n-9) content, while the Hereford breed had the lowest (P < 0.01). The highest ALA, DPA, total EPA + DHA, total EPA + DHA + DPA and total ALA + EPA + DHA + DPA contents were detected in the Wagyu breed (P ≤ 0.03). The Hereford had similar EPA and DPA contents to the Angus (P ≥ 0.46). Total EPA + DHA + DPA contents in Wagyu, Angus, and Hereford were 28.8, 21.5, and 22.1 mg/100g tissue (P = 0.01), respectively. Sex was an important source of variation that influenced LC omega-3 PUFA composition, FMP and IMF, where yearling heifers had higher IMF (11.9% vs 5.3%), lower FMP (33°C vs 37°C), and higher LC omega-3 PUFA than bulls. CONCLUSION: All the results taken together indicate that the Wagyu breed at 28.8 mg/100g tissue, was the closest to meeting the Australia and New Zealand recommended source level threshold of 30 mg/100g tissue of health-beneficial ≥ C20 omega-3 FA content. Since gender was a significant determinant of LC omega-3 PUFA composition, IMF content and FMP, it should be factored into enhancement strategies of healthy meat eating quality traits in grazing cattle. These findings also suggest that the Bowen Genetics Forest Pastoral beef cattle studs are important sources of LC omega-3 PUFA that can be used to cover the deficit in these health claimable fatty acids in Western diets.

The Crystallization and Melting Behavior of Neodymium-Based Butadiene Rubber Blends.

This study investigates the influence of poly(butadiene-isoprene) copolymer rubber (BIR) and TDAE oil on the crystallization and melting behavior of neodymium-based butadiene rubber (Nd-BR). The study demonstrates that the melting points of Nd-BR and its blends decrease with lower crystallization temperatures. Below the critical crystallization temperature (Tc,c), the melting behavior shows dual peaks in distinct temperature ranges, which are attributed to different spherulitic sizes. The addition of BIR or TDAE oil lowers the Tc,c, with TDAE oil exerting a more substantial effect. These diluents mainly influence the nucleation temperature and crystallinity level of Nd-BR while having a minimal effect on the crystallization mechanism. A master curve, which overlaps for various samples, is developed by correlating the peak melting temperature (Tm,peak) with the Tc. This curve facilitates a quantitative assessment of the effects of BIR and TDAE oil on Nd-BR, highlighting the greater influence of TDAE oil on the crystalline structure compared with BIR at equivalent mass fractions. By applying the Lorentz equation and multi-peak fitting, a relationship between the melting points and crystallization temperatures is established, enabling the calculation of the equilibrium melting points (Tm0) for different samples. The findings show a reduction in the Tm0 due to the diluents; specifically, the Tm0 is approximately 0 °C for pure Nd-BR, and it decreases to -4.579 °C and -6.579 °C for samples with 50 PHR TDAE oil and 60 wt.% BIR, respectively.

Synthesis of Calamitic Fluorinated Mesogens with Complex Crystallization Behavior.

This work presents the synthesis and self-organization of the calamitic fluorinated mesogen, 1,1,2,2-tetrafluoro-2-(1,1,2,2-tetrafluoro-4-iodobutoxy)ethanesulfonic acid, a potential model for perfluorosulfonic acid membranes (PFSA). The compound is derived in three steps from 1,1,2,2-tetrafluoro-2-(1,1,2,2-tetrafluoro-2-iodoethoxy)ethanesulfonyl fluoride, achieving a 78% overall yield. The resulting compound exhibits intricate thermal behavior. At 150 °C, a crystal-to-crystal transition is observed due to the partial disordering of calamitic molecules, which is followed by isotropization at 218 °C. Upon cooling, sample ordering occurs through the formation of large smectic liquid crystalline phase domains. This thermotropic state transforms into a layered crystal phase at lower temperatures, characterized by alternating hydrophilic and hydrophobic layers. Using X-ray diffraction, crystalline unit cell models at both room temperature and 170 °C were proposed. Computer simulations of the molecule across varying temperatures support the idea that thermal transitions correlate with a loss of molecular orientation. Importantly, the study underscores the pivotal role of precursor self-organization in aligning channels during membrane fabrication, ensuring controlled and oriented positioning.

Eutectic phase transition during tablet manufacture: effect of melting point of eutectic forming drug.

The aim was to investigate eutectic transition during tableting and storage. Mixtures of lidocaine and series of NSAIDs with increasing melting point were used as model systems to guide formulators to scaleup eutectic forming materials gaining enhanced dissolution while avoiding deleterious physical changes. Physical mixtures of NSAIDs with lidocaine were prepared at eutectic forming ratio. These were directly compressed, dry co-ground before compression, or compressed after wet granulation. Dissolution of tablets was compared to corresponding dry co-ground mixture. Thermograms of direct compressed tablet were compared to co-ground mixture and pure compound. Stability of direct compressed tablets was assessed. Tableting initiated eutexia which enhanced dissolution of NSAIDs. Eutexia was associated with tablet softening in case of low melting point ketoprofen and aceclofenac. Wet granulation hastened eutexia developing unacceptable tablet in case ketoprofen and aceclofenac. Tablets prepared by direct compression of physical mixtures underwent gradual eutectic transition upon storage with the magnitude of eutectic transition reducing with increased melting point of NSAIDs. Ketoprofen was physically unstable but aceclofenac degraded chemically as well. Tenoxicam and meloxicam tablets were physically and chemically stable. Direct compression after physical mixing is the best tableting technique, but low melting point drugs should consider different strategy before compression.

Oxygen-Containing Quaternary Phosphonium Salts (oxy-QPSs): Synthesis, Properties, and Cellulose Dissolution.

In the present study, the synthesis of oxygen-containing quaternary phosphonium salts (oxy-QPSs) was described. Within this work, structure-property relationships of oxy-QPSs were estimated by systematic analysis of physical-chemical properties. The influence of the oxygen-containing substituent was examined by comparing the properties of oxy-QPSs in homology series as well as with phosphonium analog-included alkyl side chains. The crystal structure analysis showed that the oxygen introduction influences the conformation of the side chain of the oxy-QPS. It was found that oxy-QPSs, using an aprotic co-solvent, dimethylsulfoxide (DMSO), can dissolve microcrystalline cellulose. The cellulose dissolution in oxy-QPSs appeared to be dependent on the functional group in the cation and anion nature. For the selected conditions, dissolution of up to 5 wt% of cellulose was observed. The antimicrobial activity of oxy-QPSs under study was expected to be low. The biocompatibility of oxy-QPSs with fermentative microbes was tested on non-pathogenic Saccharomyces cerevisiae, Lactobacillus plantarum, and Bacillus subtilis. This reliably allows one to safely address the combined biomass destruction and enzyme hydrolysis processes in one pot.

First-Principles Study on Si Atom Diffusion Behavior in Ni-Based Superalloys.

The Si atom diffusion behavior in Ni-based superalloys was evaluated based on first-principles calculations. Also, the site occupation of Si atoms as the melting point depressant elements in Cr, Mo, and W atom doped γ-Ni and γ'-Ni3Fe supercells was discussed and Si atom diffusion behaviors between both adjacent octahedral interstices were analyzed. Calculation results indicated that formation enthalpy (∆Hf) was decreased, stability was improved by doping alloying elements Cr, Mo, and W in γ-Ni and γ'-Ni3Fe supercells, Si atoms were more inclined to occupy octahedral interstices and the diffusion energy barrier was increased by increasing the radius of the doped alloy element. Especially, two diffusion paths were available for Si atoms in the γ'-Ni3Fe and Si diffusion energy barrier around the shared Fe atoms between adjacent octahedral interstices and was significantly lower than that around the shared Ni atoms. The increase of interaction strength between the doped M atom/octahedron constituent atom and Si atom increased Si atom diffusion and decreased the diffusion energy barrier. The Si atom diffusion behavior provides a theoretical basis for the phase structure evolution in wide-gap brazed joints.

Long-Term Aging Study on the Solid State Interfacial Reactions of In on Cu Substrate.

Indium is considered a candidate low-temperature solder because of its low melting temperature and excellent mechanical properties. However, the solid-state microstructure evolution of In with different substrates has rarely been studied due to the softness of In. To overcome this difficulty, cryogenic broad Ar+ beam ion polishing was used to produce an artifact-free Cu/In interface for observation. In this study, we accomplished phase identification and microstructure investigation at the Cu/In interface after long-term thermal aging. CuIn2 was observed to grow at the Cu/In interface and proved to be a stable phase in the Cu-In binary system. The peritectoid temperature of the Cu11In9 + In → CuIn2 reaction was confirmed to be between 100 and 120 °C. In addition, the growth rate of CuIn2 was discovered to be dominated by the curvature of the reactant Cu11In9/In phase and the temperature difference with the peritectoid temperature. Finally, a comprehensive microstructural evolution mechanism of the Cu/In solid-state interfacial reaction was proposed.

Advancements in Phase Change Materials in Asphalt Pavements for Mitigation of Urban Heat Island Effect: Bibliometric Analysis and Systematic Review.

This research presents a dual-pronged bibliometric and systematic review of the integration of phase change materials (PCM) in asphalt pavements to counteract the urban heat island (UHI) effect. The bibliometric approach discerns the evolution of PCM-inclusion asphalt research, highlighting a marked rise in the number of publications between 2019 and 2022. Notably, Chang'an University in China has emerged as a leading contributor. The systematic review addresses key questions like optimal PCM types for UHI effect mitigation, strategies for PCM leakage prevention in asphalt, and effects on mechanical properties. The findings identify polyethylene glycols (PEGs), especially PEG2000 and PEG4000, as prevailing PCM due to their wide phase-change temperature range and significant enthalpy during phase transitions. While including PCM can modify asphalt's mechanical attributes, such mixtures typically stay within performance norms. This review emphasises the potential of PCM in urban heat management and the need for further research to achieve optimal thermal and mechanical balance.

A Study on Tencel/LMPET-TPU/Triclosan Laminated Membranes: Excellent Water Resistance and Antimicrobial Ability.

Medical product contamination has become a threatening issue against human health, which is the main reason why protective nonwoven fabrics have gained considerable attention. In the present, there is a soaring number of studies on establishing protection systems with nonwoven composites via needle punch. Meanwhile, the disadvantages of composites, such as poor mechanical performance and texture, impose restrictions. Hence, in this study, an eco-friendly method composed of needling, hot pressing, and lamination is applied to produce water-resistant, windproof, and antimicrobial Tencel/low-melting-point polyester-thermoplastic polyurethane/Triclosan (Tencel/LMPET-TPU/TCL) laminated membranes. Field-emission scanning electron microscope (SEM) images and FTIR show needle-punched Tencel/LMPET membranes successfully coated with TPU/TCL laminated membranes, thereby extensively improving nonwoven membranes in terms of water-resistant, windproof, and antimicrobial attributes. Parameters including needle punch depth, content of LMPET fibers, and concentration of TCL are changed during the production. Specifically, Tencel/LMPET-TPU/TCL-0.1 laminated nonwovens acquire good water resistance (100 kPa), outstanding windproof performance (<0.1 cm3/cm2/s), and good antimicrobial ability against Escherichia coli and Staphylococcus aureus. Made with a green production process that is pollution-free, the proposed products are windproof, water resistant, and antimicrobial, which ensures promising uses in the medical and protective textile fields.

The Relationship Between Molecular Symmetry and Physicochemical Properties Involving Boiling and Melting of Organic Compounds.

OBJECTIVE AND METHODS: The reliable estimation of phase transition physicochemical properties such as boiling and melting points can be valuable when designing compounds with desired physicochemical properties. This study explores the role of external rotational symmetry in determining boiling and melting points of select organic compounds. Using experimental data from the literature, the entropies of boiling and fusion were obtained for 541 compounds. The statistical significance of external rotational symmetry number on entropies of phase change was determined by using multiple linear regression. In addition, a series of aliphatic hydrocarbons, polysubstituted benzenes, and di-substituted napthalenes are used as examples to demonstrate the role of external symmetry on transition temperature. RESULTS: The results reveal that symmetry is not well correlated with boiling point but is statistically significant in melting point. CONCLUSION: The lack of correlation between the boiling point and the symmetry number reflects the fact that molecules have a high degree of rotational freedom in both the liquid and the vapor. On the other hand, the strong relationship between symmetry and melting point reflects the fact that molecules are rotationally restricted in the crystal but not in the liquid. Since the symmetry number is equal to the number of ways that the molecule can be properly oriented for incorporation into the crystal lattice, it is a significant determinant of the melting point.

Effects of Bi-Sn-Pb Alloy and Ball-Milling Duration on the Reactivity of Magnesium-Aluminum Waste-Based Materials for Hydrogen Production.

In the present study, composite materials were elaborated of mixed scrap of Mg-based casting alloys and low melting point Bi-Sn-Pb alloy by high energy ball milling, and their reactivity in NaCl solution with hydrogen release was tested. The impacts of the additive content and ball milling duration on their microstructure and hydrogen generation performance were investigated. Scanning electron microscopy (SEM) analysis revealed significant microstructural transformations of the particles during milling, and X-ray diffraction analysis (XRD) proved the formation of new intermetallic phases Mg3Bi2, Mg2Sn, and Mg2Pb. The said intermetallic phases were anticipated to act as 'microcathodes' enhancing galvanic corrosion of the base metal. The dependency of the samples' reactivity on the additive content and milling duration was determined to be nonmonotonic. For the samples with 0, 2.5, and 5 wt.% Rose alloy, ball-milling during 1 h provided the highest hydrogen generation rates and yields (as compared to 0.5 and 2 h), while in the case of the maximum 10 wt.%, the optimal time shifted to 0.5 h. The sample activated with 10 wt.% Rose alloy for 0.5 h provided the highest 'metal-to-hydrogen' yield and rapid reaction, thus overperforming those with lower additive contents and that without additives.

Preparation of a novel healthy tiger nut oil-based margarine fat with low trans and saturated fatty acids.

The present study sought to develop a novel healthy margarine fat with low levels of trans and saturated fatty acids in order to promote healthier alternatives. In this work, tiger nut oil was first used as a raw material to prepare margarine fat. The effects of mass ratio, reaction temperature, catalyst dosage, and time on the interesterification reaction were investigated and optimized. The results showed that, the margarine fat with ≤40% saturated fatty acids was achieved using a 6:4 mass ratio of tiger nut oil to palm stearin. The ideal interesterification parameters were 80 °C, 0.36% (w/w) catalyst dosage, and 32 min. Compared with physical blends, the interesterified oil had lower solid fat content (3.71% at 35 °C), lower slip melting point (33.5 °C), and lower levels of tri-saturated triacylglycerols (1.27%). This investigation provides important information for the utilization of tiger nut oil in healthy margarine formulation.

Direct observation of concentration fluctuations in Au-Si eutectic liquid by small-angle neutron scattering.

It is well-known that eutectic gold-silicon (Au-Si) alloys exhibit anomalous melting point depression, which is more than 1000 °C from the melting point of elemental Si (1414 °C). The melting point depression in eutectic alloys is generally explained in terms of a decrease of the free energy by mixing. However, it is difficult to understand the anomalous melting point depression only from the stability of the homogeneous mixing. Some researchers suggest that there are concentration fluctuations in the liquids, where the atoms are inhomogeneously mixed. In this paper, we measure the small-angle neutron scattering (SANS) of Au81.4Si18.6(eutectic composition) and Au75Si25(off-eutectic composition) at temperatures from room temperature to 900 °C in both solid and liquid states to observe such concentration fluctuations directly. It is surprising that large SANS signals are observed in the liquids. This indicates that there are concentration fluctuations in the liquids. The concentration fluctuations are characterized by either the correlation lengths in multiple length scales or surface fractals. This finding yields new insight into the mixing state in the eutectic liquids. The mechanism of the anomalous melting point depression is discussed based on the concentration fluctuations.

Sintering densification mechanism and mechanical properties of the 3D-printed high-melting-point-difference magnesium oxide/calcium phosphate composite bio-ceramic scaffold.

Over the past few years, biodegradable ceramic scaffolds have gained significant attention in the field of bone repair. Calcium phosphate (Ca3(PO4)2)- and magnesium oxide (MgO)-based ceramics are biocompatible, osteogenic, and biodegradable, making them attractive for potential applications. However, the mechanical properties of Ca3(PO4)2 are limited. We developed a magnesium oxide/calcium phosphate composite bio-ceramic scaffold characterized by a high melting point difference, using vat photopolymerization (VP) technology to address this issue. The primary goal was to fabricate high-strength ceramic scaffolds using biodegradable materials. In this study, we investigated ceramic scaffolds with varying MgO contents and sintering temperatures. We also discussed the co-sintering densification mechanism of high and low melting-point materials associated with composite ceramic scaffolds. During sintering, a liquid phase was generated, which filled up the pores generated during the vaporization of additives (such as resin) under the influence of capillary force. This led to an increase in the extent of ceramic densification realized. Moreover, we found ceramic scaffolds with 80 wt% MgO exhibited the best mechanical performance. This kind of composite scaffold performed better than pure MgO scaffold. The results reported herein highlight that high-density composite ceramic scaffolds can be potentially used in the field of bone repair.

Modified Born method for modeling melting temperature usingab initiomolecular dynamics.

The prediction of a material's melting point through computational methods is a very difficult problem due to system size requirements, computational efficiency and accuracy within current models. In this work, we have used a newly developed metric to analyze the trends within the elastic tensor elements as a function of temperature to determine the melting point of Au, Na, Ni, SiO2and Ti within ±20 K. This work uses our previously developed method of calculating the elastic constants at finite temperatures, as well as leveraging those calculations into a modified Born method for predicting melting point. While this method proves to be computationally expensive, the level of accuracy of these predictions is very difficult to reach using other existing computational methods.

Enhanced Hydrogen Generation from Magnesium-Aluminum Scrap Ball Milled with Low Melting Point Solder Alloy.

In this investigation, composite materials were manufactured of mixed scrap of Mg-based alloys and low melting point Sn-Pb eutectic by high energy ball milling, and their hydrogen generation performance was tested in NaCl solution. The effects of the ball milling duration and additive content on their microstructure and reactivity were investigated. Scanning electron microscopy (SEM) analysis indicated notable structural transformations of the particles during ball milling, and X-ray diffraction analysis (XRD) proved the formation of new intermetallic phases Mg2Sn and Mg2Pb, which were aimed to augment galvanic corrosion of the base metal. The dependency of the material's reactivity on the activation time and additive content occurred to be non-monotonic. For all tested samples ball milling during the 1 h provided, the highest hydrogen generation rates and yields as compared to 0.5 and 2 h and compositions with 5 wt.% of the Sn-Pb alloy, demonstrated higher reactivity than those with 0, 2.5, and 10 wt.%.

Isobaric Thermal Expansivity and Isothermal Compressibility of Liquid Metals.

The relationship between the volumetric thermodynamic coefficients of liquid metals at the melting point and interatomic bond energy was studied. Using dimensional analysis, we obtained equations that connect cohesive energy with thermodynamic coefficients. The relationships were confirmed by experimental data for alkali, alkaline earth, rare earth, and transition metals. Cohesive energy is proportional to the square root of the ratio of melting point Tm divided by thermal expansivity αp. Thermal expansivity does not depend on the atomic size and atomic vibration amplitude. Bulk compressibility ßT and internal pressure pi are related to the atomic vibration amplitude by an exponential dependence. Thermal pressure pth decreases with an increasing atomic size. Fcc and hcp metals with high packing density, as well as alkali metals, have the relationships with the highest coefficient of determination. The contribution of electrons and atomic vibrations to the Grüneisen parameter can be calculated for liquid metals at their melting point.

Controllable Crystallization of Two-Dimensional Bi Nanocrystals with Morphology-Boosted CO2 Electroreduction in Wide pH Environments.

Two-dimensional low-melting-point (LMP) metal nanocrystals are attracting increasing attention with broad and irreplaceable applications due to their unique surface and topological structures. However, the chemical synthesis, especially the fine control over the nucleation (reduction) and growth (crystallization), of such LMP metal nanocrystals remains elusive as limited by the challenges of low standard redox potential, low melting point, poor crystalline symmetry, etc. Here, a controllable reduction-melting-crystallization (RMC) protocol to synthesize free-standing and surfactant-free bismuth nanocrystals with tunable dimensions, morphologies, and surface structures is presented. Especially, ultrathin bismuth nanosheets with flat or jagged surfaces/edges can be prepared with high selectivity. The jagged bismuth nanosheets, with abundant surface steps and defects, exhibit boosted electrocatalytic CO2 reduction performances in acidic, neutral, and alkaline aqueous solutions, achieving the maximum selectivity of near unity at the current density of 210 mA cm-2 for formate evolution under ambient conditions. This work creates the RMC pathway for the synthesis of free-standing two-dimensional LMP metal nanomaterials and may find broader applicability in more interdisciplinary applications.