The potential of 3,3,3-trifluoro-1-(2-pyridyl)prop-1-en-2-ol (tfppOH) as a precursor to synthesize air-stable heavier tetrylenes (HTs), either free or coordinated, was examined. Thus, the stability toward air and water of the homoleptic HTs E(tfppO)2 (E = Ge (1Ge), Sn (1Sn)), which were previously reported by Mathur and coworkers and claimed to be highly air-stable, was evaluated together with that of the novel heteroleptic chloro-HTs E(tfppO)Cl (E = Ge (2Ge), Sn (2Sn)). These analyses have shown that all these compounds are susceptible to undergo hydrolysis at room temperature, albeit at very different rates for each HT. DFT calculations have been used to study the mechanism of these hydrolytic processes. Additionally, a preliminary study of the coordination chemistry of these HTs was conducted. The reactions of 0.5 equiv of [Ir2Cl2(μ-Cl)2(η5-Cp*)2] with 2Ge cleanly afforded the Ge-Ir complex [IrCl2(η5-Cp*){κ1Ge-Ge(tfppO)Cl}] (3Ge); however, the analogous stannylene 2Sn led to a complex mixture, and the homoleptic derivatives 1E resulted in ligand degradation (formation of the HT-free complex [IrCl(η5-Cp*){κ2N,O-(tfppO)}] (4)). The Ge-Au complexes [AuCl{κ1Ge-Ge(tfppO)2}] (5Ge) and [AuCl{κ1Ge-Ge(tfppO)2}2] (6Ge) could be prepared by reacting 1Ge with [AuCl(tht)] (tht = tetrahydrothiophene); however, only the precipitation of dark-purple solids was observed using 1Sn. On the other hand, both 1E were capable of rendering the diHT-Ag analogous compounds [Ag{κ1E-E(tfppO)2}2]OTf (E = Ge (7Ge), Sn (7Sn)) in their reactions with AgOTf. The air-stability of all these complexes in solution was proven to be similar or lower (for 7Sn) than that of the corresponding metal-free HTs.

Conventional lithium extraction methods exhibit limited efficiency in strongly acidic solutions. This study developed a brand-new and universal lithium recovery strategy from strongly acidic systems using Li+ migration between directionally formed solid phase of lithium-aluminum layered double hydroxides (Li/Al-LDHs) and alternate aqueous solutions. Li+ ions in strongly acidic solutions with massive coexisting cations (Na+, K+, Fe2+, Ca2+, Mg2+, Al3+, etc.) were inductively converted into the solid precipitate through a precise crystal phase regulation. A non-equilibrium thermodynamic model was developed and revealed that the lithium deintercalation flux exhibited a linear dependence on the chemical potential gradient, systematically elucidating the critical parameters governing extraction efficiency. Subsequently, lithium extraction from Li+-enriched solid could be accomplished easily using neutral aqueous solutions with a complete delithiation, and the overall lithium recovery from acidic systems exceeded 96% with the residual solid recycling process and waste-free disposal. Furthermore, the lithium extraction strategy was proven applicable in authentic multi-component acidic solutions with efficient lithium recovery and low costs. This work is expected to significantly promote the development of universal extreme system lithium separation technology.

Water-soluble polymers, such as polyacrylamide (PAM), are industrially important chemicals that end up in our wastewater streams. Their free-radical degradation impacts the fate and treatment during use and in waste streams, the understanding of which is limited to oxidative chain scission at relatively low polymer concentrations. Here, using persulfate as the radical source, we demonstrated that cross-linking could dominate over chain scission under oxic conditions at industrially relevant high polymer and radical concentrations. Due to cross-linking, hydrogel-like solids precipitated from the solutions, the extent of which increased with concentrations of PAM and persulfate and with radical-to-polymer ratio. X-ray photoelectron spectroscopy and sulfate analysis revealed the incorporation of inorganic ions into the solid. Some solids could be redissolved in water and were more cross-linked than the cross-linked polymer that remained dissolved. A higher initial molecular weight of PAM (40-150 kDa) further promoted an earlier solid precipitation during the reaction-cooling process at lower PAM and radical concentrations; the solids were water-insoluble due to the high degree of cross-linking. These findings challenge the conventional understanding of free-radical polymer degradation and highlight the role of cross-linking, which can drastically change the environmental mobility, biodegradability/bioavailability, and treatability of PAM in waste streams.

The solid-state transformation theory has been used to describe the formation of CuO nanowires during the oxidation of Cu metal in air. In order to fill the gaps of the nucleation mechanism of CuO nanowires, a quantitative model has been founded based on the classical nucleation theory, and the results show that the formation of the CuO nanowires is controlled by a solid solution precipitation process under steady-state heterogeneous nucleation circumstances, which will provide beneficial references for the analysis and preparation of metal oxide nanowires of other metal elements.

This study addresses the challenge of through-hole defects in ZM6 cast magnesium alloy components by proposing an innovative repair strategy using ultrasonic-assisted Tungsten Inert Gas (U-TIG) welding. The microstructure and mechanical properties of the repaired joint were systematically characterized through optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and room-temperature tensile testing. The results indicate that, assisted by the ultrasonic energy field, the repair zone successfully reconstitutes a typical and optimized triple-phase microstructure: (1) the matrix: α-Mg solid solution (dark gray), supersaturated with Nd and Zr; (2) the strengthening phase: a eutectic Mg12Nd phase (light gray), rich in Nd, distributed along grain boundaries acting as the primary strengthening component; (3) the grain refiner: dispersed Zr-rich particles (bright white spots), which effectively pin grain boundaries. Crucially, the application of ultrasound significantly refined the α-Mg grains and transformed the continuous network of the Mg12Nd phase into a more fragmented and uniform dispersion. This refined microstructure synergistically integrates the strengthening mechanisms of solid solution, precipitation hardening, and grain refinement. Consequently, the repaired joint exhibits excellent mechanical properties, achieving over 90% of the base metal’s tensile strength and elongation at room temperature. This work not only validates the feasibility of U-TIG welding for repairing ZM6 alloys but also provides a solid theoretical foundation and a promising technical pathway for the in-service repair and remanufacturing of high-performance magnesium alloy components.

Enhancing the tribological performance of titanium alloy with laser-cladded Cu-containing coating

Membraneless compartmentalization via liquid-liquid phase separation (LLPS) has emerged as a powerful strategy to organize biochemical reactions. Recently, peptide-based coacervates demonstrated the potential to function as microreactors by enhancing reaction kinetics through increased local concentrations and altered microenvironments. Here, we introduce an O-methylated diphenylalanine-based tripeptide LLLPFF-OCH3 containing an N-terminal proline, designed to undergo LLPS, and simultaneously function as an enantioselective organocatalyst. Comprehensive characterization via confocal microscopy, fluorescence recovery after photobleaching (FRAP), micro-Raman and attenuated total reflection infrared (ATR-IR) spectroscopy, diffusion-surface plasmon resonance (D-SPR), and molecular dynamics (MD) simulations revealed the formation of stable liquid droplets. In contrast, a racemic mixture of LLLPFF-OCH3 and DDDPFF-OCH3 failed to form liquid droplets and instead formed a solid precipitate, unveiling a critical role of enantiopurity in LLPS. Proof-of-concept catalytic studies proved enantioselective organocatalytic activity of the LLLPFF-OCH3 liquid coacervates. Beyond catalysis these results may have broader implications in understanding prebiotic chemistry and neurodegeneration.

Polyelectrolyte complexes(PECs) can exist as liquidcoacervatesor solid precipitates with triggers such as salt, pH, or temperaturedriving transitions. However, it is unclear how enzymatic chain scissionreorganizes solid PECs and alters their mechanics. We probed cellulase-mediatedremodeling of solid PECs formed from carboxymethyl cellulose (CMC)and short or long poly­(diallyldimethylammonium chloride) (PDADMAC).Turbidity and microscopy showed that short PDADMAC/CMC complexes decreasedin turbidity and became liquid-like as enzyme dose and time increased.In contrast, long PDADMAC complexes exhibited a transient turbidityincrease at high cellulase concentration and formed droplet-like phasesconsistent with competing PDADMAC/cellulase coacervation. Zeta potentialsupported cellulase binding to PDADMAC, which reduced the positivecharge available for CMC bridging. Rheology showed dose- and time-dependentsoftening, while long PDADMAC remained more elastic and relaxed moreslowly. Thus, the enzyme dose and polycation length jointly controlthe kinetics of coupled structural and mechanical transitions in solidPECs.

Abstract Titanium aluminide (TiAl)-based alloys are high-temperature material with potential to replace heavier superalloys like Ni-based alloys. This is because of their lightweight which makes TiAl-based alloys favorable for aerospace engine application, but low ductility, and fracture toughness limit their structural applicability. Moreover, in material science and engineering research, it is essential to achieve adequate balance in terms of strength and ductility without sacrificing other important material properties. Thus, the aim of this study is to investigate the influence of heat treatment on the microstructure and mechanical properties of TiAlSi-3.7Mo and TiAlSi-13.7 V alloys synthesized using laser in situ alloying. Heat treatment was performed at 1200 °C and 1400 °C for 60 minutes, followed by furnace cooling (FC). The microstructure and composition were examined using scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS); phases identification was carried out with the aid of an x-ray diffractometer (XRD) and electron backscattered diffraction (EBSD). The Anton Paar nanoindentation tester was used to investigate the nanomechanical properties, while the Vickers hardness tester was used to determine the microhardness values. It was observed that dual-phased (DP) and fully lamellar (FL) microstructures were present at 1200 °C and 1400 °C, respectively, with varying amounts of β 0 and ζ-Ti 5 Si 3 precipitating phases along the grain boundaries depending on the alloying element (Mo and V) present. The phase analysis reveals the presence of γ , α 2 , α , β 0 , and ζ-Ti 5 Si 3 phases in the as-built alloys. The β 0 -TiAl and ζ-Ti 5 Si 3 phases exhibit solid precipitation hardening and solution strengthening at grain boundaries due to Mo and Si interactions. The alloy with V inclusion showed improved mechanical properties, particularly after heat treatment, by increasing the formation of α 2 + γ lamellae. This study demonstrated that V and Mo additions to Ti-Al-Si alloy sample showed improved mechanical properties after heat treatments.

Wire-based friction stir additive manufacturing of AZ31B magnesium alloy: Precipitate behavior and mechanical properties

The multi-objective optimization of multicomponent superalloys has long been impeded by not only the complex interactions among multiple elements but also the low efficiency and high cost of traditional trial-and-error methods. To address this issue, this study proposed a thermodynamic calculation data-driven optimization framework that integrates machine learning (ML) and multi-objective screening based on domain knowledge. The core of this methodology involves introducing a commercial reference alloy and rapidly generating a large-scale thermodynamic dataset through ML models. After training, the ML models were verified to be more efficient at predicting phase transition temperatures and γ′ volume fractions than the CALPHAD methods. Focusing on the mechanical properties, critical strength indices, including solid solution strengthening, precipitation strengthening, and creep resistance based on the calculated γ/γ′ two-phase compositions, were compared with the reference alloy and set as the critical screen criteria. Optimal alloys were selected from the 388,000 candidates. Compared with the reference alloy, two new alloys were experimentally verified to have superior or comparable compressive yield strength and creep resistance at 900 °C at the expense of oxidation resistance and density, while maintaining comparable cost. This work demonstrates the significant potential of combining high-throughput thermodynamic data with intelligent multi-objective optimization to accelerate the development of new alloys with tailored property profiles.

Abstract Concrete degradation is often caused by the formation of new solid phases within the pore network of cement, leading to crack formation and propagation, ultimately resulting in structural damage. In this study, we propose a coarse-grained particle-based model to simulate solid growth in porous networks. The model combines Grand Canonical Monte Carlo simulations for solid precipitation with molecular dynamics simulations in the isobaric–isothermal ensemble to capture crack formation. The model is applied to investigate the formation of ice in cement paste during freeze-thaw cycles, focusing specifically on the freezing stage. The simulation results revealed a two-stage growth process: an initial lag phase where isolated ice clusters grow within pores, followed by a rapid growth phase during which the ice clusters percolate through the pore network. This percolation is associated with significant volume expansion and fracture of the cement paste, providing insights into the mechanisms driving freeze-thaw damage in cement-based materials.

The effectiveness of Fiber-Reinforced Polymer (FRP) reinforced with Engineered Cementitious Composites (ECC) for strengthening concrete structures is critically dependent on the interfacial bond between the ECC overlay and the substrate concrete. This study investigates the efficacy of interfacial agents in enhancing this bond and delves into the underlying mechanisms through single-sided shear tests and micro-scale measurements. The results demonstrate that the application of a silicate-based activator including titanium fluoride (Z3 agent) yielded the most significant improvements, with increases of 70.8% in shear strength compared to untreated specimens. Micro-scale analysis revealed that the Z3 agent deeply penetrates the interfacial transition zone, reacting with free Ca(OH)2 to form solid precipitates that densify the pore structure and enhance mechanical properties. Based on the experimental data, a highly accurate practical model for predicting bond strength is proposed, which explicitly incorporates the contributions of surface roughness, concrete strength, and the interfacial agent.

Reactive pathways of synthetic forsterite and Mg/Ni-serpentine: Insights into incipient dissolution and carbonation

Preparation of lyophilized nanocrystals of poorly soluble drugs using solid dispersion-mediated precipitation and high-pressure homogenization

• The concentrations of most trace and toxic elements in CarbFix1 and CarbFix2 waters were low. • These concentrations were substantially lower than that estimated from stoichiometric basalt dissolution. • Low concentrations of trace and toxic elements are consistent with secondary mineral precipitation of carbonates and sulfides. • Results suggest negligible risk of substantial water contamination from dissolved CO 2 and H 2 S injection into basalts. Carbon dioxide storage through the carbonation of subsurface basaltic rocks is currently being explored to limit carbon emissions to the atmosphere. Basaltic rocks, however, contain trace and toxic metals that could potentially be mobilized by the carbonation process. This study reports the degree to which selected trace and toxic metals were mobilized during CarbFix1 and CarbFix2 projects. CarbFix1 injected 175 tons of CO 2 -charged water followed by 73 tons of CO 2 /H 2 S-charged water into basalts at 35 °C, whereas CarbFix2 continuously injected CO 2 /H 2 S-charged water into basalts at >250 °C. In most cases dissolved concentrations of Ba, Sr, Mo, Cu, Cr, Ni, Cd, and Pb in monitoring well fluids remained low. Although these fluids are not intended for human consumption, the aqueous trace element concentrations were generally below the WHO, EU, and Iceland drinking water standards, except for Fe and Mn in CarbFix1. Aluminum and As concentrations exceeded these standards during CarbFix2, but were elevated before injection. The low concentrations of most trace and toxic metals are consistent with their removal by secondary processes, particularly co-precipitation into carbonate and sulfide minerals formed during gas-water-basalt interaction. Solid precipitates recovered from CarbFix1 show strong enrichment of transition metals in calcite, consistent with natural and engineered analogues. As the two CarbFix injections bound the lower and upper temperature ranges of likely mineral carbon storage efforts, these results suggest limited risk of water contamination due to toxic and trace element release from subsurface basalts due to the injection of dissolved CO 2 and H 2 S.

Droplet microfluidics, which generates and manipulates water-in-oil microdroplets within continuous phases, has emerged as a compelling platform in modern science. The core advantage of this technology lies in the fact that each picoliter to nanoliter droplet functions as an independent microreactor, ensuring no cross-contamination. This enables ultra-high-throughput experiments while dramatically reducing the consumption of expensive reagents and rare samples. However, the efficient extraction of solid precipitates (such as crystals and particles) formed within droplets remains a fundamental challenge for subsequent analysis and utilization. This study proposes a novel microfluidic device and operational method to address these challenges: (1) the difficulty in extracting solids that cannot be recovered through simple fluid flow and (2) sample loss during long-distance transport. The key innovation combines (1) a passive trap structure for in situ solid formation processes within droplets and (2) a physically accessible harvesting chamber positioned nearby. This design eliminates the need for long-distance sample transport, enabling the gentle transfer of droplets containing precipitated solids to an adjacent extraction chamber with an open top, allowing for physical solid recovery. We demonstrated the system functionality using fluorescent microbeads as model particles, followed by the successful generation and recovery of protein (lysozyme) crystals as a practical application.

Background and purposeThe pH-dependent solubility of imipramine, a tricyclic antidepressant, and its hydrochloride salt was investigated in phosphate buffers and chloride-containing aqueous media using the pH-ramp shake-flask method. It was reported that aggregation of imipramine in acidic media and its partial degradation in alkaline media complicate the determination of its solubility. This was further investigated with modified methods.Experimental approachFor imipramine solubility studies, the computer program pDISOL-X was used to design experiments, process data, and refine the equilibrium constants. Isolated solid precipitates under various conditions were characterized using thermogravimetric analysis, differential scanning calorimetry, powder X-ray diffraction, and elemental analysis. The critical micelle concentration of imipramine hydrochloride was determined in 0.10 mol L-1 NaH2PO4 and in 0.15 mol L-1 NaCl by conductometric titrations.Key resultsA detailed analysis of imipramine pH-solubility profiles reveals complex equilibria in the aqueous phase, as well as various solid-phase transformations. Intrinsic solubility of imipramine, solubility products of imipramine hydrochloride and imipramine phosphate salts, and aggregation constants (trimer, heptamer, and cationic complex with phosphate ions) were determined. Solid state characterization results are in accordance with pDISOL-X analysis.ConclusionThese findings, along with our previous solubility studies of desipramine and nortriptyline, suggest that even subtle structural variations can lead to significant differences in the aqueous media behaviour of tricyclic antidepressants. This type of information can be valuable in the early stages of drug discovery, in formulation optimization experiments, as well as in in vitro and in vivo studies.

Abstract Monitoring environmental activities of radiocarbon ( 14 C) requires specific preparation procedures and measurement techniques. For 14 C in air samples, trapped by bubbling in NaOH solutions, the most used technique is the precipitation of carbon as BaCO 3 and activity quantification by liquid scintillation counting (LSC). However, the main drawback is that the solid precipitate in the scintillation cocktail did not form a clear and homogeneous solution in the vial during the measurement period. This issue leads to variability in the quenching effect, poor precision and repeatability, and high detection limits. In the literature, a methodology was proposed using Insta-Gel Plus scintillation cocktail, which can form a gel with the precipitate. In our study, carbonate mass and ultrasonic agitation were optimized, the quenching value remains constant throughout the measurement period, leading to more precise measurements and a lower detection limit. The method was validated using environmental samples previously characterized by accelerator mass spectrometry, as well as spiked samples at very low levels, close to the detection limit. This detection limit was estimated at 0.12 Bq/L or 90 Bq/kg C, demonstrating the method’s capability to analyze 14 C in air samples at environmental levels without influence from nuclear industry.

Abstract Patagonia Icefields are large ice masses with a significant contribution to sea level rise among mountain glaciers in the Southern Hemisphere. In order to improve the estimation of the Northern Patagonia Icefield (NPI) surface mass balance and to better understand its relationship with climate variables and modes, we simulated the surface mass balance over the icefield during the period 1980–2014 with the MAR model. Model reliability was assessed against: weather stations, albedo from MODIS data and previous estimates of the San Rafael glacier’s surface mass balance. We obtain a surface mass balance of –2.48 ± 1.86 Gta –1 and a non-significant trend. Temperature (a physically downscaled variable) was a key variable through its direct impact on melting, but also on solid precipitation. We found that the annual, spring and autumn icefield mean surface mass balance had a significant negative correlation with the Southern Annular Mode (SAM) through air temperature. Over the next century, the impacts of greenhouse gas emissions are projected to keep the SAM in a positive phase and accelerate atmospheric warming. Thus, the NPI is expected to increase its mass loss and its contribution to future sea level rise. However, more in-situ data (precipitation, temperature and accumulation/ablation on the icefield) are needed to improve the projection’s uncertainty.