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Thermodynamic properties of homogeneous fluids in the metastable and unstable regions are needed to describe confined fluids, interfaces, nucleating embryos and estimate critical mass flow rates. The most accurate equations of state (EoS) called multiparameter EoS, have a second, non-physical Maxwell loop that renders predictions unreliable in these regions. We elaborate how information from the stable region can be used to reconstruct the metastable and unstable regions. For a simple interaction potential, comparison to results from molecular simulations reveals that isochoric expansion of the pressure from stable states reproduces simulation results in the metastable regions. By constructing a dome that extends above the critical point, we obtain an extrapolated pressure from multiparameter EoS that is free of second Maxwell loops. A reconstructed EoS is developed next, by integrating the extrapolated pressure from a stable state to obtain the Helmholtz energy. The consistency of the reconstructed EoS is gauged by computing phase equilibrium densities, pressures, and enthalpies of evaporation, which are in reasonable agreement with experimental values. Combined with density gradient theory, the reconstructed EoS yields surface tensions of water, carbon dioxide, ammonia, hydrogen and propane that deviate, on average, 4.4%, 1.6%, 6.0%, 0.7% and 5.4% from experimental values respectively. The results reveal a potential to develop more accurate extrapolation protocols, which can be leveraged to obtain prediction of metastable properties, surface properties or used as constraints in fitting multiparameter EoS. [ABSTRACT FROM AUTHOR]

Electrolyte-assisted semiconductors have garnered significant attention as a novel type of semiconductor device due to their unique properties. Notably, the electrolyte-assisted electroluminescent (EEL) device offers several advantages, including a simple structure, low operating voltage, and reduced need for band engineering compared to conventional EL devices. However, achieving practical applications for EEL devices remains challenging due to their inherent issues. In this study, we introduce a yellow-emitting EEL device that utilizes a metastable β-phase Zn 2 SiO 4 :Mn2+ film as the optically functional material. The film is prepared using a cost-effective process, optimizing both the crystallization temperature and the concentration of Mn2+. Additionally, we employ a non-toxic aqueous NaCl as the electrolyte in the device setup. The crystal phase, morphology, optical, and electrical properties, along with reliability, are comprehensively investigated in our study. The results highlight the significance of our proposed work in advancing the development of electrolyte-assisted semiconductors within the realm of silicon photonics. • A yellow electrolyte-assisted electroluminescent (EEL) device is presented using metastable optical material in an electrolyte-silicon semiconductor structure. • The EEL optimum of annealing temperature, dopant, and electro-optical properties are investigated. • The EEL device reliability and post-operation morphology are examined to evaluate the practicality and prospects. [ABSTRACT FROM AUTHOR]

The metastable Ni/ZrO 2 catalysts were rationally constructed via reflux treatment and employed for dry reforming of methane. Reflux could suppress the transformation and improve the stability of the metastable ZrO 2 , as well as enrich its pore structure. Meanwhile, acidity-basicity, Zr3+ and oxygen vacancies were also promoted. Additionally, Ni dispersion was remarkably improved with increasing reflux time due to the abundant pores and enhanced metal-support interaction. These results illustrated the evaluation that prolonging reflux time could significantly proliferate the performance of Ni/ZrO 2. Besides, reflux could strengthen the anti-carbon ability but the widened gap between CH 4 dissociation and CO 2 activation would cause more carbon deposition. The catalyst with reflux for 240 h showed the robust stability for 9000 min (CH 4 conversion: 80 %; CO 2 conversion: 88 %) at 750 °C. Furthermore, the mechanisms were discussed to unravel the origin of the accelerated performance by reflux and provide some references for designing efficient Ni-based catalyst. [Display omitted] • Reflux stabilizes the metastable ZrO 2 with abundant pore structure and more acid-base/defect sites. • Reflux enhances metal-support interaction, thereby improving Ni dispersion. • Catalyst after reflux shows higher activity, better stability and stronger anti-carbon ability. • Balancing the rate of CH 4 dissociation and CO 2 activation is crucial for restraining carbon formation. • Reaction mechanisms are discussed to unravel the origin for the performance improvement by reflux. [ABSTRACT FROM AUTHOR]

Rendering any surface non-wettable requires it to be clean and dry after the droplet is deposited or impacted. Leveraging and quantifying the non-periodic or random topology non-wettable is intricate as the Cassie-Baxter state competes with the Wenzel or impaled state, which becomes further challenging for irregular and heterogeneous nonwoven materials. Herein, we report the fundamental insights of the impalement dynamics of droplets on metastable nonwovens and self-similar nonwoven-titanate nanostructured materials (SS-Ti-NMs) using laser scanning confocal microscopy in three dimensions. Our results represent the first example of liquid imbibition in metastable nonwovens and SS-Ti-NMs involving a complex interplay between a triumvirate of factors – the number of fibres in the defined cross-sectional area (volume), pore features, and intrinsic wetting properties of the constituent entities. Predictive models of the apparent contact angle and breakthrough pressure for nonwovens and their SS-Ti-NMs have been proposed based on micro- and nano-scale structural parameters. Enabled by X-ray microcomputed tomography analysis, a key set of three-dimensional fibre and structural parameters of nonwovens has been unveiled, which played a vital role in validating the predictive models of apparent contact angles. [Display omitted] [ABSTRACT FROM AUTHOR]

Face-centered cubic (fcc)-phase high-entropy alloys (HEAs) have attracted much academic interest, with the stacking fault energy (SFE) playing an important role in regulating their mechanical behaviors. Here, we revealed the principles for regulating both the elastic and plastic behaviors by composition modification and Mo addition in an fcc-phase quaternary CoCrFeNi system with the assistance of ab initio and thermodynamics calculations. An increase in Co content and a decrease in Fe and Ni contents reduced the fcc phase stability and SFE, but enhanced the elastic modulus, anisotropy, and lattice friction stress. A minor substitution of Co by Mo increased the lattice constant, but decreased the SFE and elastic modulus. Based on these findings, we developed a series of strong and ductile metastable fcc-phase Co x Cr 25 (FeNi) 70- x Mo 5 (x = 30, 40, 50) HEAs with mechanical properties superior to those of the CoCrFeNi HEAs. The careful investigation revealed that the enhanced mechanical properties are due to the Mo-addition-induced strengthening accompanied with a low-SFE-induced restriction of planar behavior of dislocations, mechanical twinning, and strain-induced martensitic transformation. The findings shed light on the development of high-performance HEAs. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Unstable photoproducts of trenbolone and altrenogest were quantified via LC–MS/MS. • Photoproducts were generated onsite with solar simulator. • Cold, neutral conditions, fast processing, and [M + Na]+ control improve performance. • SPE extracts of photoproducts are stable for up to a month. • Sample acidification can be used to quantify photoproducts indirectly. Here, we developed a novel and sensitive method for the detection and quantification of metastable trenbolone and altrenogest photoproducts in agricultural receiving waters based on solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC–MS/MS). Primary method analytes were seven cycloaddition or photohydration transformation products of 17α-trenbolone (17α-TBOH), 17β-trenbolone (17β-TBOH), trendione (TBO), and altrenogest (ALT), which are key contributors to the fate and environmental risks of these steroidal pharmaceuticals. Because commercial analytical standards are not available, reference standards for photoproducts were generated from trenbolone or ALT with a solar simulator (˜6 h, >10 half-lives). Efficient detection of metastable photoproducts required cold and pH neutral conditions, rapid sample processing, minimal sample storage, and consideration of cationic artifacts. Method detection limits (MDLs) were 0.034-0.40 ng L−1 for parent compounds and 0.16–2.1 ng L−1 for photoproducts, sufficient for their detection in agroecosystems. Matrix suppression was observed and corrected by internal standards, and relative recovery rates were near 100% for all analytes except for 12-OH-17α-TBOH (˜75% recovery). Intra-day variation was <20% and inter-day variation <25% for all the analytes. The developed method is capable of the analysis of trenbolone, altrenogest, and their key bioactive photoproducts in agricultural receiving waters. [ABSTRACT FROM AUTHOR]

Highlights • Amorphous GeTe/cubic Sb 2 Te 3 supperlattice-like structure films were fabricated. • Supperlattice-like structure improved the thermal stability of cubic Sb 2 Te 3. • Interface influenced the phase transformation and thermodynamical stability. Abstract We fabricated the amorphous GeTe/cubic Sb 2 Te 3 supperlattice-like structure films by the radio frequency sputtering, and demonstrated the stability of cubic Sb 2 Te 3 could be strengthened. The competition between interface energy and phase transformation energy resulted in the thermodynamical stability at the nanoscale. The presented design approach opens the doors for the stabilization of metastable phase, and sheds new insights into the role of interfaces in materials synthesis. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Laser melting is known to be capable in initiating thorough evolution in microstructure and bringing novel functional performance in metals. But realization of this potential in ceramics only reaches a preliminary stage that needs further investigation. Here we demonstrate zirconia, traditionally an insulative ceramic at low temperature, could be transformed into an electronic conductor with the conductivity on order of 10−3 S⋅cm-1 at room temperature by a simple laser melting process without inducing metallic phases. Transmission electron microscopy and ab-initio simulation show that oversaturated oxygen vacancies, together with their ordered metastable distribution along <001 > , are introduced during this non-equilibrium process, and result in a clear defect level significantly narrowing bandgap to less than 1 eV, leading to the considerable electronic conductivity. These results identify a strategy of utilizing this non-equilibrium method in oxide ceramics to realize some unconventional performances determined by metastable structure thoroughly altered down to atomic level. [ABSTRACT FROM AUTHOR]

Abstract In this work, the microstructure, phase transformation, and tensile properties were investigated for Ti 55 -x Zr 20 Hf 15 Al 10 Nb x (x = 1, 2, 3..., 9, at%) medium entropy alloys (MEAs). It has been found that the phase composition of the as-cast MEAs changes from hexagonal α′ to orthorhombic α″, then to metastable β, finally to stable β phase at x = 2, 4 and 9, respectively. The phase transformation of Nb4–Nb8 MEAs evolved in the sequence of β + α″→ω + α″ + β→α + β′→β during heating process. The phase constitution and microstructure of these MEAs strongly influence their tensile properties. The formation of metastable α″ and β phase in certain compositional and temperature range results in "double yielding" phenomenon and remarkable work-hardening effect. Extraordinary static toughness represented by the product of strength and elongation has achieved for MEA with 8% Nb. The deformation mechanisms for these MEAs changes with the phase composition. For the alloy with most α″ phase, the deformation is dominated by de-twinning of martensite variants; for the alloys with most β phase, stress induced martensitic transformation from metastable β to α″ phase and the refinement of the newborn martensite by the dislocation have been verified. These integrated effects are considered to endow the MEAs excellent deformation ductility. [ABSTRACT FROM AUTHOR]

Abstract Mg-based materials have been widely researched for hydrogen storage development due to the low price of Mg, abundant resources of Mg element in the earth's crust and the high hydrogen capacity (ca. 7.7 mass% for MgH 2). However, the challenges of poor kinetics, unsuitable thermodynamic properties, large volume change during hydrogen sorption cycles have greatly hindered the practical applications. Here in this review, our recent achievements of a new research direction on Mg-based metastable nano alloys with a Body-Centered Cubic (BCC) lattice structure are summarized. Different with other metals/alloys/complex hydrides etc. which involve significant lattice structure and volume change from hydrogen introduction and release, one unique nature of this kind of metastable nano alloys is that the lattice structure does not change obviously with hydrogen absorption and desorption, which brings interesting phenomenon in microstructure properties and hydrogen storage performances (outstanding kinetics at low temperature and super high hydrogen capacity potential). The synthesis results, morphology and microstructure characterization, formation evolution mechanisms, hydrogen storage performances and geometrical effect of these metastable nano alloys are discussed. The nanostructure, fresh surface from ball milling process and fast hydrogen diffusion rate in BCC lattice structure, as well as the unique nature of maintaining original BCC metal lattice during hydrogenation result in outstanding hydrogen storage performances for Mg-based metastable nano alloys. This work may open a new sight to develop new generation hydrogen storage materials. Highlights • Our achievements on Mg-based metastable nano alloys with BCC lattice are summarized. • Uniquely, BCC metal lattice in these alloys does not change obviously with hydrogen. • This metastable feature brings interesting microstructures and hydrogen storage performance. • Mechanisms of formation, and special hydrogen storage performance are discussed. [ABSTRACT FROM AUTHOR]

Conventionally, bulk WC and Cr 3 C 2 -based carbide compositions have been used independently of each other. However, recent investigations have begun to explore combining these carbides together within the same composite/hard metal coating system. This work explored the diversity of phases produced in the coatings from a 42 wt% WC-42 wt% Cr 3 C 2 –16 wt% Ni powder sprayed under "low", "medium" and "high" thermal input conditions using high velocity oxygen-fuel (HVOF), an argon‑helium (Ar He) plasma and an argon‑hydrogen (Ar H 2) plasma respectively. The thermally driven solid-state transformations in the coatings were investigated as a function of carbide dissolution/decomposition, using differential scanning calorimetry (DSC). All coatings exhibited a well defined exothermic peak attributed to the transformation of the metastable supersaturated Ni-alloy and WC 1-X phases in the as-sprayed coatings, into the equilibrium Ni alloy and a mix of the intermediate metastable carbide phases β-W 2 C and Cr 3 C 2 - Y. At higher temperatures the metastable compounds transformed to the equilibrium phases of ε-W 2 C and Cr 3 C 2. A defining feature of the XRD analysis was the significant shift in lattice positions of all phases, indicating substitutional alloying. The mechanisms of phase formation are discussed. • A WC-Cr 3 C 2 -Ni composite powder was sprayed using HVOF and Plasma thermal spraying. • Exothermic DSC peak from 680 to 760 °C attributed to precipitation of dissolved phases. • HVOF coating formed WC, ε-W 2 C and Cr 3 C 2 - Y at 650 °C, and Cr 3 C 2 at higher temperature. • Negligible change in Plasma coating Ni alloy, WC 1-X and β-W 2 C phases up to 760 °C. • Above 760 °C, the saturated Ni alloy and WC 1-X transformed to form Cr 3 C 2 and ε-W 2 C. [ABSTRACT FROM AUTHOR]

Highlights • From the Bogoliubov inequality the mean field approximation is applied in the Ashkin-Teller model. • The stable, metastable and unstable states of a cubic structure are investigated. • From the critical values in the free energy of the model, those phases are classified. • Phase transition lines of first-order and continuous are obtained. • Multicritical points are obtained according to this procedure. Abstract The mean field approximation from the Bogoliubov inequality is applied to study the ferromagnetic Ashkin-Teller model in three dimensions. Phase transitions for the stable, metastable and unstable states is observed. From the critical values in the free energy of the model, those transitions are classified. Besides the free energy, magnetization, critical frontiers and tricritical points are obtained. Phase diagram is presented for a better illustration of the phase transitions and its order. [ABSTRACT FROM AUTHOR]

Abstract The low aqueous solubility of diazepam (DZP) presents a challenge in formulating nasal sprays without the use of organic solvents. One approach to overcome this challenge involves co-administration of a soluble prodrug, avizafone (AVF), with a converting enzyme to produce supersaturated DZP at the site of administration. In addition to overcoming solubility issues, the supersaturated state of DZP provides an increased driving force for enhanced permeation across nasal mucosa. However, supersaturated solutions are metastable, and there is a limit to the degree of supersaturation (S) that can be reached without causing spontaneous phase separation of the solute. The aim of this article was to determine how formulation parameters affect the rate of DZP supersaturation, maximum degree of supersaturation, and phase separation kinetics. A model enzyme, Aspergillus oryzae protease (AOP), was used to convert AVF to DZP, via an open ring intermediate (ORI). A second derivative UV spectroscopic method was developed to simultaneously monitor DZP solution concentration and the time course of DZP phase separation. Fitting a kinetic model, with prior knowledge of the enzyme kinetic parameters, the rate constant for conversion of ORI to DZP was found to be 0.470 ± 0.012 min−1. Kinetics and supersaturated solution stability were studied as a function of formulation parameters, including temperature, pH, buffering agent, AVF concentration, and enzyme concentration. The maximum aqueous solution concentration for DZP at 32 °C was determined to be 1.22 ± 0.03 mM DZP (S = 9.38) and was insensitive to changes in formulation parameters, excepting temperature. Supersaturated solutions of DZP could be maintained at the maximum concentration for >24 h, even in the presence of phase separated DZP. Polarized light microscopy, PXRD, and DSC analysis indicated that the phase separated DZP was amorphous upon formation and remained so for >24 h. Our findings suggest that co-administration of AVF with a suitable human converting enzyme will provide a viable mechanism for IN delivery of DZP and result in very rapid and complete absorption to quickly terminate seizure emergencies. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract The development of novel high-temperature structural and multifunctional thermal protection materials for harsh environment applications, such as high-temperature oxidation, severe thermal shock, ablation by combustion gas flow etc., is one of the urgent needs of the modern aerospace industry. Ceramic matrix composites such as C f /(C, SiC, Si 3 N 4 ), SiC f /ZrB 2 , SiC p /(Si 3 N 4 , HfB 2 ) have received much attention in recent years. Coincidently, metastable silicoboron carbonitride (Si-B-C-N) ceramics and corresponding matrix composites stand out from all recent materials offering great potential at high temperatures due to their high microstructural stability and excellent high-temperature properties including resistance to oxidation, thermal shock and ablation. Using inorganic powders (such as Si, C, B, BN, etc.) instead of organic precursor as raw materials, the inorganic processing route based on mechanical alloying (MA), one of the non-equilibrium processing technique, coupled with sequential sintering, although apparently very ‘hard’ compared to the ‘soft’ polymer precursor method, is actually a simple and effective way to prepare monoliths with the uniform microstructures and superior properties. It has been used to obtain dense Si-B-C-N monoliths and structural parts stable at high temperatures providing new experimental data and therefrom a more detailed understanding of the intrinsic properties of metastable Si-B-C-N materials, benefitting progress towards engineering applications. This review summarizes the state-of-the-art research in Si-B-C-N ceramics and their matrix composites obtained by the inorganic processing route in the last decade compared with those of precursor-derived counterparts, including material design and preparation, microstructural features and evolutionary process, mechanical and thermophysical properties, resistance to oxidation, thermal shock and ablation, and the mechanisms of oxidation, ablation and crystallization of amorphous Si-B-C-N ceramics. Future trends for Si-B-C-N relevant materials are also pointed out. [ABSTRACT FROM AUTHOR]

The stability of the γ′-Ni 2 Cr long-range order (LRO) phase present on the Ni-Cr binary phase diagram was examined in a Ni-55Cr (wt. %) alloy. It is shown that the γ′-Ni 2 Cr phase is metastable, and that the two-phase γ-Ni + α-Cr phase field extends to room temperature. The as-cast alloy consisted of a typical dendritic microstructure, with Cr-rich primary α-Cr dendrites and a Cr-lean, γ-Ni interdendritic. Annealing the as-cast alloy at 500 °C for 1000 h (γ′-Ni 2 Cr + α-Cr phase field) resulted in pockets of α-Cr and γ-Ni + γ′-Ni 2 Cr at the dendritic/interdendritic interface, with little change to the interdendritic γ-Ni microstructure. Annealing at 900 °C for 4 h (γ-Ni + α-Cr phase field) resulted in the interdendritic precipitation of α-Cr, both as a continuous and discontinuous precipitate. Annealing at 900 °C for 4 h followed by 500 °C for 1000 h resulted in the interdendritic precipitation of α-Cr at 900 °C, but no precipitation of γ′-Ni 2 Cr during subsequent annealing at 500 °C. This behavior suggests that the γ′-Ni 2 Cr phase is not the equilibrium phase, but rather a metastable transition phase. Furthermore, it is speculated that this phase in more complex alloys (i.e. Alloy 690) is also metastable, and its metastability should be considered in applications involving long-term, high temperature exposures. [ABSTRACT FROM AUTHOR]

Rare earth elements are recently attracting more and more interests due to their dramatic effect as alloying elements. However the study regarding the phase equilibria between rare earth elements are still rare. The thermodynamically stable phases within the ∼50 at.%Y region have been investigated for the La-Y binary system using differential scanning calorimetry, scanning electron microscopy and transmission electron microscopy in the present work. The samarium-type δ-LaY has been found to be unstable while a pure Y phase with fcc crystal structure has been observed. A new invariant reaction has been determined to be bcc-(La,Y) + fcc-Y → dhcp-(La,Y) at 717 ± 3 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • Key to accurate measuring segregation lies in acquiring stable fluidization state. • Two methods to obtain stable fluidization state for binary particles were compared. • The second method had greater applicability to obtain stable fluidization state. • Difficulty in obtaining stable fluidization state resulted from internal friction. • Binary particles could be polymorphic in state at U g ranging from U mfF to U mfJ. Co-fluidization of two types of particles is commonly encountered in the chemical and energy industry. A deep understanding of segregation between them is of great significance. The accurate measurement of segregation for any gas velocity (U g) from the experimental perspective is the first and critical step. The key lies in acquiring the stable fluidization state that could represent the given U g. Two distinct methods were thoroughly compared in this work. The first was decreasing gas flow quickly from high values to the target U g and keeping fluidization therein for sufficient time. The second was reducing gas flow very slowly from high values to the target U g. The apparent minimum fluidization velocity of the binary particles was denoted as U mfa whereas the minimum fluidization velocities of flotsam and jetsam were represented by U mfF and U mfJ. When U g was greater than U mfJ , the corresponding stable fluidization state could be easily reached via either method. Yet, it could only be acquired via the second method for U g ∈(U mfa , U mfJ). For U g ∈(U mfF , U mfa), neither method was feasible. The difficulty in acquiring the stable fluidization state for U g < U mfJ resulted eventually from the internal friction among the particles, due to which the de-fluidization of some jetsam particles could deprive the capability of many other particles to move and hinder their migration to the stable equilibrium positions. The macroscopic state of binary particles at U g ∈(U mfF , U mfJ) was further found to depend also on the path taken to reach it; binary particles therein could have different equilibrium states (being polymorphic); the final fluidization state acquired via the first method was demonstrated to be metastable. The stable fluidization state of binary particles at U g ∈(U mfF , U mfa) was too complicated to describe; convincing methods for acquiring it and determining the true extent of segregation are of urgent need; the second method was still effective in approaching the so-called stable fluidization state. [ABSTRACT FROM AUTHOR]

Manganese oxides are metastable phases due to oxygen loss at high temperature. Conventional ceramic routes need high temperature and thus are unsuitable for making MnO x foams. A mild templating route at 300–400 °C was developed to construct metastable MnO x foams. Interwoven OMS-2 (cryptomelane) nanofibers with a length-diameter ratio of ca. 3000 over a template may create an OMS-2 foam at 400 °C with an atmosphere of 21% O 2 content, a MnO/C foam at 400 °C with an atmosphere of 0% O 2 content, OMS-2/Mn 3 O 4 foams at 400 °C with an atmosphere of 1–5% O 2 content, or Mn 3 O 4 /MnO 2 foams at 300–350 °C in an atmosphere of 1% O 2 content. Three foam materials are materials with ductility while others belong to brittle materials. [ABSTRACT FROM AUTHOR]

Non-consumable arc melting was used to produce buttons of transition metal (Co-Cu-Fe) high entropy alloys (HEAs) with additions of Al, Cr, Mn, Ni, V or Ti. High resolution scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) capabilities were used for microstructural characterization. It was found that certain HEAs exhibit stable liquid miscibility gaps causing separation into two liquids, namely a Cu-lean liquid, L1, and a Cu-rich liquid, L2. Since, in stable liquid phase separation (LPS) involving Cu, the Cu-rich L2 has a higher density and a lower melting temperature, it sinks to the bottom of the casting. Secondary melt separation was also observed and resulted in small spheres of the minority liquid embedded in the matrix of the first liquid. Additions of Co, Al, Ti, and Ni were found to lower the miscibility gap temperature (T MG ), while additions of Cr, V, and Nb were observed to raise T MG and enhance stable LPS. Thermodynamic calculations were used to support the experimental results. [ABSTRACT FROM AUTHOR]

Chemical braking occurs in a dilute solution during a structural change of ethynylhelicene ( M )-nonamer from the metastable double-helix state to the random-coil state, being at equilibrium, where the reaction is initially rapid and then substantially retard. The chemical braking is derived from the competitive chemical reaction system in dilute solution: An energetically uphill self-catalytic reaction to form double-helix and the downhill reaction to form the random-coil. [ABSTRACT FROM AUTHOR]

The present work focuses on studying the relationship between the time period of a polymer solution staying in the metastable region and the resulting porous structure after phase separation of the solution. We employed the technique of FTIR microscopy to determine the composition change in the PMMA/NMP ( n -methylpyrrolidone) solution after its contact with water. By plotting the composition change on the ternary phase diagram of PMMA, NMP and water, and identifying the times that the composition path intersected with the binodal and the spinodal, we then determined the residence time of the solution in the metastable region (t m ). For each polymer solution, we identified a critical residence time (t mc ) that played a dominant role in determining the phase separation mechanism and the resulting porous structure: with t m less than t mc , the corresponding structure was bi-continuous (typical structure resulted from spinodal decomposition); with t m greater than t mc , the corresponding structure was cellular (typical structure from the mechanism of nucleation and growth). The results show that t mc depended on the polymer molecular weight and the polymer concentration in casting solution. And the dependences can be superimposed into one curve as the polymer concentration was normalized by the polymer chain entanglement concentration. With the relationship between t mc and the normalized polymer concentration and a simple model for the effective diffusivity of water in the polymer solution, we developed a model equation to estimate the positions in PMMA membranes where structure transition occurred from bi-continuous to cellular. Good agreement was obtained between the calculated transition positions and the experimentally determined ones. [ABSTRACT FROM AUTHOR]

Dynamics of coupled Brownian particles with color correlated additive Gaussian colored noises in a metastable state is analyzed to study the phenomenon of noise enhanced stability. The lifetime of such a metastable state is found to depend on the noise correlations and initial conditions. Dynamics of the slow variable is analyzed using the method of adiabatic elimination in the weak color limit. [ABSTRACT FROM AUTHOR]

Complementary b/y fragment ion pairs from post-source decay (PSD) of metastable YahO protein ion were evaluated for use in the calibration of MALDI-TOF-TOF for tandem mass spectrometry (MS/MS). The yahO gene from pathogenic Escherichia coli O157:H7 strain EDL933 was cloned into a pBAD18 plasmid vector and transferred to a yahO gene knockout (Δ yahO ) of non-pathogenic Escherichia coli strain K-12. YahO protein was over-expressed by overnight culturing of the K-12 mutant on Luria-Bertani agar (LBA) supplemented with arabinose. MS/MS-PSD of the YahO protein ion results in polypeptide backbone cleavage on the C-terminal side of seven aspartic acid (D) residues of the mature protein sequence resulting in a series of prominent b/y fragment ion pairs. Interestingly, we observe an unusual oscillatory pattern in the fragmentation efficiency of cleavage sites across the linear polypeptide chain of YahO. The instrument was calibrated for MS/MS-PSD using at least six of twelve of the most intense b- and y-type fragment ions of YahO. Calibration was tested on the disulfide bond-reduced B-subunit of Shiga toxin 2 from Escherichia coli O157:H7 strain EDL933 cultured overnight on LBA supplemented with ciprofloxacin. Two non-simultaneous calibrant/analyte acquisition scenarios were evaluated: 1. YahO and B-subunit on separate (but adjacent) spot locations; 2. YahO and the B-subunit co-located on the same spot. We observed no significant difference in mass accuracy for co-location vs. adjacent spot analysis in spite of a significant drop in ion intensity of both calibrant and analyte for co-location analysis. [ABSTRACT FROM AUTHOR]

• A new methodology for determining the nucleation temperatures of water is described. • The new methodology predicts higher nucleation temperatures than the previous ones. • New approximations of nucleation temperatures as functions of the heating rate. • Attention is focused on heating rates in the range 10 6 to 10 9 K/s. • New approximations are expected to be useful for modelling puffing/micro-explosions. The previously developed experimental methodologies for determining the nucleation temperatures of water at atmospheric pressure are critically reviewed and further developed. Particular attention is focused on the methodology, in which a special approach that regulates the details of the setup of the experiments and the procedure for translating primary data into required liquid temperatures at the onset of boiling is set out. It is pointed out that following the latter methodology, either partially or fully, leads to a prediction of higher nucleation temperatures of water at atmospheric pressure compared with most previous predictions of this temperature in the range of heating rates (T ˙) 10 6 K / s to 10 9 K / s. New approximations for the nucleation temperature as a function of the heating rate are suggested in the ranges 10 2 K / s to 10 4 K / s and 10 6 K / s to 10 9 K / s , based on the amended and revised experimental data. These approximations are expected to have a wide range of applications, including in the analysis of timing of puffing/micro-explosion in composite water/fuel droplets, inkjet printing, Nano/Micro electro-mechanical systems (N/MEMS), and in the nuclear and medical industries. [ABSTRACT FROM AUTHOR]

[Display omitted] The limited coercivity (H c) and metastability of the ferromagnetic τ phase MnAl-C magnet have constrained its magnetic performance and application potential. Bi was doped into the Mn 54 Al 44-x Bi x C 2 alloy system in this study. The doped Bi could effectively stabilize the metastable τ phase and inhibit the non-magnetic Al-rich phase formation. The ferromagnetic τ phase ratio increased dramatically as the doped Bi increase, with a peak M s of 81 emu/g was achieved for the post-annealed Mn 54 Al 43.6 Bi 0.4 C 2 alloy at 19 kOe. High H c ferromagnetic LTP MnBi phase forms within the Mn 54 Al 44-x Bi x C 2 (x = 0.2, 0.4, 0.6) alloys when it been annealed at 300℃ for 24 h, the samples tripled or even quadrupled in H c compared with the initial synthesized alloy. The doped Bi dissolved within lattice caused the τ phase thermally stability, structural stability improves substantially; 0.4 Bi doped Mn 54 Al 43.6 Bi 0.4 C 2 alloy exhibited a combination of high M s and H c even after been ball milled for a long period of 15 and 20 h. The (M s , H c) achieved a value of (59.6 emu/g, 3526 Oe) for the 15 h milled sample and (51.5 emu/g, 4546 Oe) for the 20 h milled sample at 19 kOe, respectively; which is desirable for its application as a high-performance rare earth free permanent magnet. [ABSTRACT FROM AUTHOR]

Metastable eutectic melting of solid mixture NaCl + H 2 O was measured in a wide range of its compositions by using a DSC. The new eutectic melting was found to occur near −27 °C, below the well know ice-NaCl∙2H 2 O eutectic point (−21.1 °C, 23.3 wt.%) of equilibrium both phase diagram. The new low-temperature eutectic was detected for all samples, in two-phase regions, Н 2 О-NaCl∙2H 2 O and NaCl∙2H 2 O-NaCl. The new eutectic temperature is close to the value of ∼−28 °C reported by Roedder (1984) for the mixture of solid H 2 O and NaCl, which was never repeated or reaffirmed independently since then. The heat effect of the metastable eutectic melting did allow us to estimate the enthalpy of formation of hydrohalite from salt and ice: NaCl(cr) + 2H 2 O(cr) = NaCl∙2H 2 O(cr) + Δ H (= −0.73 ± 0.07 kJ mol −1 ). [ABSTRACT FROM AUTHOR]

The phase transition of active pharmaceutical ingredients should be taken into account during manufacturing, processing- and storage, because different crystal forms lead to different physical properties of formulations. The phase transition of clarithromycin (CAM) metastable form I to stable form II was investigated on heating with additives such as fatty acids or fatty acid esters. Differential scanning calorimetry analyses revealed that when form I was heated with additives, the phase transition temperature of form I decreased close to the melting points of the additives. Powder X-ray diffraction analyses indicated the tentative presence of a non-crystalline component during the transition of form I to form II on heating with additives. These observations implied that CAM form I dissolved in the melted additives on heating and the dissolved CAM crystallized to form II. Reduction of transition temperatures in the presence of additives were also observed for the crystals of nifedipine form B and carbamazepine form III. These results suggested that the phenomena can be widely applicable for simultaneous crystalline phase transition and granulation using binder additives. [ABSTRACT FROM AUTHOR]

This paper describes research into development of a rapid-turnaround, neutron-spectroscopy capable (gamma-beta blind), high intrinsic efficiency sensor system utilizing the tensioned metastable fluid detector (TMFD) architecture. The inability of prevailing theoretical models (developed successfully for the classical bubble chamber) to adequately predict detection thresholds for tensioned metastable fluid conditions is described. Techniques are presented to overcome these inherent shortcomings, leading thereafter, to allow successful neutron spectroscopy using TMFDs – via the newly developed Single Atom Spectroscopy (SAS) approach. SAS also allows for a unique means for rapidly determining neutron energy thresholds with TMFDs. This is accomplished by simplifying the problem of determining Cavitation Detection Events (CDEs) arising from neutron interactions with one in which several recoiling atom species contribute to CDEs, to one in which only one dominant recoil atom need be considered. The chosen fluid is Heptane (C 7 H 16 ) for which only recoiling C atoms contribute to CDEs. Using the SAS approach, the threshold curve for Heptane was derived using isotope neutron source data, and then validated against experiments with mono-energetic (2.45/14 MeV) neutrons from D-D and D-T accelerators. Thereafter the threshold curves were used to produce the response matrix for various geometries. The response matrices were in turn combined with experimental data to recover the continuous spectra of fission (Cf-252) and (α,n) Pu–Be isotopic neutron sources via an unfolding algorithm. A generalized algorithm is also presented for performing neutron spectroscopy using any other TMFD fluid that meets the SAS approach assumptions. [ABSTRACT FROM AUTHOR]

A magnetic-field-induced irreversible metamagnetic phase transition from antiferro- to ferromagnetism, which leads to an anomalous initial-magnetization curve lying outside the magnetic hysteresis loop, is reported in arc-melted SmCo 7− x Si x alloys. The transition temperatures are near room temperature, much higher than other compounds with similar initial curves. Detailed investigation shows that this phenomenon is dependent on temperature, magnetic field and Si content and shows some interesting characteristics. It is suggested that varying interactions between the Sm and Co layers in the crystal are responsible for the formation of a metastable AFM structure, which induces the anomalous phenomenon in as-cast alloys. The random occupation of 3 g sites by Si and Co atoms also has an effect on this phenomenon. [ABSTRACT FROM AUTHOR]

The participation of small H 2 molecules in hydrate formation generally includes single and multiple occupancy, and the state could vary frequently due to their high fluidity. In this study, distinctly split DSC peaks for hydrate dissociation in constant CO 2 /H 2 gas phase systems were found, which generally means the coexistence of several hydrates with different phase equilibrium temperatures. Based on the results of hydrate equilibrium decomposition conditions and decomposition enthalpies, we attributed the occurrence of this peculiar phenomenon mainly to different occupation patterns of H 2 molecules in hydrate cages. However, several occupancies in the mild conditions of this study may be metastable, which was significantly related to H 2 escape. Raman results demonstrated the existence of single occupancy of H 2 molecule in both of the 512 and 51262 cages. In addition, co-existing of CO 2 and H 2 in 51262 cage may also be detected. The effects of hydrate formation time and morphology on the split DSC peaks further indicated the occupation-related H 2 molecule aggregation and probabilistic escape. The discovery in this work may provide some new insights into the deeper understanding of the physical/chemical properties behind clathrate hydrate in the future. The different occupation patterns of H 2 molecules in hydrate cages. [Display omitted] • Splitting DSC peaks for hydrate dissociation in constant CO 2 /H 2 systems were found. • The peculiar phenomenon attributes to the different occupation patterns of H 2 molecules in hydrate cages. • Several occupancies in mild conditions are metastable which is related to H 2 escape. • There exists single occupancy of H 2 molecule in both of the 512 and 51,262 cages. • The co-existing of CO 2 and H 2 in 51,262 cage is detected. [ABSTRACT FROM AUTHOR]

Crystal phase of semiconductor nanocatalysts has a great influence on their catalytic performance. Ag-based nanomaterials are fascinating electrocatalysts for CO 2 reduction reaction (CO 2 RR) toward CO formation. However, the phase-dependent catalytic behavior of Ag-based electrocatalysts has not been studied so far. Herein, we report a crystal phase-dependent catalytic behavior of Ag 2 Se nanoparticles based on the successful synthesis of monoclinic (m -Ag 2 Se) and orthorhombic (o -Ag 2 Se). Remarkably, m -Ag 2 Se nanoparticles deliver an enhanced CO Faradic efficiency up to 98.1 % at −0.90 V vs. RHE as well as the long-term stability under an extremely high current density, far exceeding that of o -Ag 2 Se. Theoretical simulations reveal that m -Ag 2 Se surface not only facilitates the adsorption and stabilization of *COOH species, but also tends to inhibit HER, thus accounting for the high activity and selectivity for CO formation during CO 2 RR. This work offers new insights into the facile design of electrocatalysts in catalysis via crystal phase structure regulation. [Display omitted] • Different crystal phases Ag 2 Se including monoclinic Ag 2 Se (m -Ag 2 Se) and orthorhombic Ag 2 Se (o -Ag 2 Se) are fabricated. • Electrocatalytic CO 2 reduction on m -Ag 2 Se achieves a selectivity of 98.1 % for the generation of CO. • A set of physicochemical measurements and DFT calculations have been performed to probe the electrocatalytic mechanism. [ABSTRACT FROM AUTHOR]

We report in this study detailed measurements of optical characteristics of the barrier discharge filled with Ne (50 %) and Xe (50 %) gas compositions. The discharge is driven by a sinusoidal voltage regime and was achieved and studied in the pressure of 250 mbar, at frequency of 40 kHz and for applied voltage going from 800 V up to 2 kV. The input electric power is measured with an oscilloscope, combined with a voltage probe and a current probe. The light intensity for the spectral region from 200 nm to 1100 nm was measured with a optical spectrometer. The lamp spectrum contained 826,877 nm, 822,021 nm, 879,995 nm, 881,999 nm, 902,998 nm and 915,011 nm radiations is studied in order to analysis the chemical kinetics in Ne/Xe mixture flat lamp in DBD emitting in the infrared (IR) and visible band. This study is done to explain the role of excited higher states in production of metastable states of xenon responsible for UV emission. The results discuss the effect of applied voltage and for different gas pressure on the luminance and efficacy of the lamp. The results predict that under the typical operating conditions of the DBD the total efficiency is very high with an optimum pressure at 400 mbar and an optimum voltage of 1200 V. [ABSTRACT FROM AUTHOR]

The development of metastable titanium (Ti) alloys provides an unprecedented opportunity to expand their use in plasticity and damage critical applications like protective structures. However, such applications require knowledge of quasi-static to dynamic mechanical behavior, which is currently lacking. Here we perform in-situ, ultrafast synchrotron x-ray diffraction during high strain rate (Kolsky) pressure bar testing in tension and post-mortem electron microscopy to study TRansformation Induced Plasticity (TRIP) and TWinning Induced Plasticity (TWIP) in metastable Ti-Mo alloys. Two alloys, namely Ti-12Mo and Ti-15Mo (wt. %), were selected for study having different β -phase chemical stabilities. TWIP was observed in both Ti-12Mo and Ti-15Mo by in-situ synchrotron diffraction during high strain rate testing. Post-mortem microstructural characterization also revealed the presence of TRIP in Ti-12Mo. TWIP in Ti-15Mo was found to under-perform in terms of total elongation compared to TRIP/TWIP in Ti-12Mo. Ti-12Mo exhibited an average elongation of 17% compared to only 12% for Ti-15Mo with deformation at 1000 s−1. TRIP resulted in significantly finer microstructure evolution and alleviated local strain accumulations in Ti-12Mo, suggesting TRIP can be used to tune available strength/ductility combinations in metastable Ti alloys under high strain rate deformation conditions. [ABSTRACT FROM AUTHOR]

Metastable MgO x N y compound was synthesized through annealing under the mixture of nitrogen–oxygen gases. The nanocrystalline particles of different morphology were formed. Powders were characterized by XRD, SEM, TEM, Raman spectroscopy. A complete synthesis of MgO x N y was obtained upon annealing at 650 °C with low BET surface area when compared to Mg 3 N 2 powder. [ABSTRACT FROM AUTHOR]

A density function theory (DFT) approach was used for understanding the stable and metastable interfacial structures observed experimentally in Mg/Nb multilayer films. Different types of interfaces, including the hcp Mg(0 0 0 1)/bcc Nb(1 1 0), the bcc Mg(1 1 0)/bcc Nb(1 1 0), and the hcp Mg(0 0 0 1)/hcp Nb(0 0 0 1), were investigated. The calculated interfacial energies help rationalize the stabilization of metastable interfaces involving bcc Mg-like arrangements in the experimentally characterized Mg/Nb multilayers. Electronic charge properties of the interfacial slabs are compared to corresponding bulk structures. The metallic bonding present in the thin film models has been explained by electron localized function and density of state analysis. [ABSTRACT FROM AUTHOR]

An improved thermodynamic model of the Fe–Co phase diagram has been achieved by incorporating new experimental data that was obtained via containerless processing. Fe–Co samples were prepared with 30, 40, and 50 at% cobalt, and they were processed via electrostatic levitation (ESL). The samples were levitated, melted, and allowed to cool and solidify in a vacuum. If sufficient undercooling was achieved, the metastable phase was observable after the first recalescence, which gives information on the location of the projected metastable phase lines on the phase diagram. Based on these new results, several parameters were adjusted so that the phase lines better represented the experimental metastable data, while the rest of the phase diagram continues to accurately predict previously accepted experimental results. The improved phase diagram allowed for evaluation of key solidification parameters including the partitioning coefficient of the metastable phase, as well as the thermal driving potential for the solidification of the stable phase from the metastable phase. [ABSTRACT FROM AUTHOR]

We study the metastability and nucleation of the Blume–Capel model on complex networks, in which each node can take one of three possible spin variables { − 1 , 0 , 1 } . We consider the external magnetic field h to be positive, and let the chemical potential λ vary between − h and h in a low temperature, such that the 1 configuration is stable, and − 1 configuration and/or 0 configuration are metastable. Combining the heterogeneous mean-field theory with simulations, we show that there exist four regions with distinct nucleation scenarios depending on the values of h and λ : the system undergoes a two-step nucleation process from − 1 configuration to 0 configuration and then to 1 configuration (region I); nucleation becomes a one-step process without an intermediate metastable configuration directly from − 1 configuration to 1 configuration (region II(1)) or directly from 0 configuration to 1 configuration (region II(2)) depending on the sign of λ ; the metastability of the system vanishes and nucleation is thus irrelevant (region III). Furthermore, we show that in the region I nucleation rates for each step intersect that results in the occurrence of a maximum in the total nucleation rate. [ABSTRACT FROM AUTHOR]

Electrospun polydiacetylenes (PDAs) composite materials are favorable for practical applications. However, a further understanding of the colorimetric changes of the composite systems in terms of thermodynamic and metastable states resulting from the interactions among multiple components is normally neglected. Herein, we functionalized diacetylenes with a variety of head groups and used them to prepare electrospun films with polyethylene oxide (PEO) as the matrix. Detailed investigations have been performed on the thermochromic properties of the PDA/PEO composite films to profile their general energy landscapes that describe the identified metastable and thermodynamic colorimetric states. Underlying mechanisms for the generation of multiple energy minima were proposed on the basis of chemical structures of PDA head groups. Utilizing the fined-tuned chromic responsiveness of the PDA/PEO composite films under thermo- and pH stimulations, as well as the features of thermodynamic and metastable states, we fabricated delicate devices for secret codes with multiple deciphering pathways and temperature sensors with a high-temperature recording function. [Display omitted] • Construction of electrospun PDA/PEO composite films with fine-tuned thermochromic properties and reversibility. • Identification of the metastable and thermodynamic colorimetric states in each PDA/PEO composite system. • Fabrication of secret codes with multiple deciphering pathways and high-temperature recording temperature sensors. [ABSTRACT FROM AUTHOR]

TiO 0.61 N 0.29 was synthesized by annealing of ball milled Ti in air at 900 °C for 5 h. In addition, traces of rutile-type TiO 1.56 N 0.56 phases were observed. The morphology of the synthesized powder displayed multiple interesting colours. Scanning electron microscopy, X-ray diffraction and Raman spectroscopy were used for characterization of the powders. Raman analyses showed a phase transformation upon annealing in air. [ABSTRACT FROM AUTHOR]

We report the single crystal diffraction study of a dimorphic 7-benzoyl-1,3-dihydroindol-2-one system and evaluate its stability relationships through thermal, grinding and slurry methods. Computational methods are invoked to understand the stability relationships. The form I crystallizes in the triclinic space group P 1 ¯ with two molecules in the asymmetric unit ( Z ′ = 2), whereas, form II crystallizes in the monoclinic space group P 2 1 / c with a single molecule in the asymmetric unit ( Z ′ = 1). The molecules exhibit subtle conformational variations along the bond connecting the phenyl and indole rings and adopt different crystal packing. While both polymorphs show similar amide dimer of N H⋯O interactions, they do differ significantly in the way the amide dimers are packed. The Differential Scanning Calorimetry (DSC), phase transformation studies and lattice energy calculations clearly established the greater stability of high Z ′ form over low Z ′ form, which contradicts the widely accepted notion that Z ′ > 1 structures are usually kinetic (or metastable). The choice of two different orientations of phenyl rings in form I enforces shorter π⋯π interactions and additional C H⋯π contacts to result in the extra stabilization energy over form II crystal packing with a single conformer. The Z ′ and stability correlation is established in 83 reported polymorphic systems which indicate that the number of stable crystal structures decrease as the Z ′ value increases. However, the polymorphic systems with Z ′ = 1 and 2 combinations are more frequently observed than any other combinations. [ABSTRACT FROM AUTHOR]

Electronic stabilities, structures, properties, and spectroscopic constants of the halogen oxide dianions OBr2- and OCl2- and their singly charged anions which are of astrophysical and laboratory interests have been studied. The X2Σ states of OBr2- and OCl2- are metastable with PECs having smooth wells with minima located at R = 1.859 Å and 1.776 Å, and Coulomb barriers of 40402.54987 cm-1 and 43746.63462 cm-1 heights located at RRCB = 2.100 Å and 1.922 Å, respectively, both without any vibrational states. While, the B2Σ state of OBr2- and the A2Σ state of OCl2- are metastable with PECs having wells deep enough to suite several bound states, with minima located at Re = 1.773 Å and 1.6430 Å, and Coulomb barriers of 191437.45813 cm-1 and 180550.70294 cm-1 heights located at RRCB = 2.658 Å and 2.4480 Å, with De = 1.26470 eV and 1.60837 eV, respectively. The OBr- and OCl- singly charged anions are stable in their ground states. Based on the calculated Frank-Condon factors, it is concluded that metastable excited state OBr2- and OCl2- dianions and ground state OBr- and OCl- singly charged anions can be formed via electron capture processes. [ABSTRACT FROM AUTHOR]

Highlights: [•] Grain growth kinetics over a wide range of temperatures from 820°C to 1000°C have been investigated. [•] The solution-treated alloy at lower temperatures exhibited a good uniformity of the grain size. [•] The abnormal grain growth at higher temperatures. [•] The lower grain growth exponent values (n) and the higher activation energy (Q) of Ti–2Al–9.2Mo–2Fe alloy. [ABSTRACT FROM AUTHOR]

Highlights: [•] Penning ionization is very efficient for the analysis of petroleum distillates with low ionization discrimination. [•] Low fragmentation extent is obtained with argon and krypton metastable atoms. [•] Coupling with FT-ICR allows using this ionization method for complex mixture analysis. [Copyright &y& Elsevier]

Abstract: The mass analysis of gas mixtures using quadrupole mass spectrometers is a well developed analytical technique which is routinely used with great success. The spectrometer's ionisation source is commonly one in which electrons from a heated filament are accelerated to around 70 eV before impacting with the gas samples. There are significant advantages, however, in being able to use other electron energies. Lower energies are particularly useful and are used in a so-called Threshold Ionisation mass spectrometry (TIMS) mode. The work described here applies the TIMS technique to a variety of problems which historically have proved to be difficult, and in some cases intractable, using the conventional mass resolved mode of mass spectrometry. The problems tackled include 4He/D2 and 3He/HD separation in nuclear fusion research, measuring trace levels of NH3 in air, and the separation of contributions from nitrogen and carbon monoxide to the QMS mass peak at m/z = 28. Finally, for measurements at higher gas pressures in the mass spectrometer, data for the production of long-lived metastable species are described. [Copyright &y& Elsevier]

Highlights: [•] The nucleus composition of metastable bcc-precipitates is modeled. [•] Enthalpies of bcc are calculated using special quasirandom structures. [•] Thermodynamic model parameters of intermetallic μ-phase are optimized. [•] The precipitate evolution in Fe–Co–Mo alloy during aging is simulated. [•] Elastic strain is considered in the precipitation simulation. [ABSTRACT FROM AUTHOR]

To ensure the safety of hydrogen systems, materials must be selected according to strength levels and susceptibility to hydrogen. Austenitic steels are notoriously resistant to hydrogen embrittlement, but usually suffer from relatively low strength levels. In this study, the material used is Fe-16Cr-10Ni, a metastable stainless steel. A slab was cold-rolled to 1.5 mm thickness and annealed to produce two different austenite grain sizes (1 μm, ultra-fine grain, and 50 μm, coarse grain). The plate material was charged in hydrogen gas (10 MPa, 270 °C, 72 hours) and the mechanical properties were evaluated by tensile testing in air. Thermal desorption spectrometry was used to confirm that there is no significant difference in hydrogen content between the two materials and that therefore grain boundaries do not play a significant role in trapping hydrogen. Tensile testing showed that the strength was increased by grain refining but that the increase in strength did not enhance the material's susceptibility to hydrogen embrittlement. Ductility, evaluated by elongation and reduction of area, decreased in both ultra-fine-grained material and coarse- grained material. Cold-rolling coupled with saturated magnetization measurements of BCC phase content showed little difference in phase transformation for hydrogen-charged and uncharged material. [ABSTRACT FROM AUTHOR]

Abstract: Metastable icosahedral quasicrystalline nanoparticles precipitate in the initial crystallization processes of some selected zirconium and hafnium based metallic glasses. All such particles reported so far are embedded in residual glassy matrix. It is predicted that, if these are separated as free standing particles, they can be applied in a variety of fields. Breaking the suitably annealed metallic glasses to small pieces by mechanical approaches is considered to be the first step toward this goal. The result of such an attempt is reported here. Several previously reported metallic glasses such as Zr70Cu27.5Rh2.5 and Hf69.5Al7.5Ni11Cu12 have been abraded by using regular sandpapers and diamond papers, scraped with diamond scratchers, and sliced by using microtome. Thus obtained small pieces have been examined by Scanning Electron Microscope, Transmission Electron Microscope, and Energy Dispersive X-ray Spectroscopy. It has been revealed that the mechanical breaking processes cause an undesired phase transformation of the quasicrystalline nanoparticles to the crystalline phases. The reason for this undesired phase transformation was analyzed and the appropriate procedures to avoid this negative effect for future work were suggested. [Copyright &y& Elsevier]

Abstract: We report a new low temperature method for the synthesis of LnNiO3 (Ln = Eu, Gd) at 400 °C under 180 bar oxygen pressure with the flux method. Utilization of the LiCl/KCl flux allowed for a decrease of the reaction temperature from 1000 °C and resulted in the synthesis of pure phase compounds. These materials have been characterized by powder X-ray diffraction and thermogravimetric analysis. LnNiO3 (Ln = Eu and Gd) compounds crystallize in the orthorhombic GdFeO3-type perovskite structure (space group: Pbnm). Both materials decompose to Ln2O3 and NiO at 775 °C under a nitrogen atmosphere and undergo reduction to Ln2O3 and Ni metal (at 385 °C and 340 °C for Eu and Gd, respectively) under a hydrogen atmosphere (10% H2/N2). Attempts to prepare the first T′-type infinite layer compound with Ni2+, EuNiO2, by low temperature reduction of EuNiO3 were unsuccessful. [Copyright &y& Elsevier]

Abstract: Physical and mathematical methods such as fluorescence and circular dichroism spectroscopies as well as MCR-ALS chemometric analysis and Wyman linkage theory were applied to assess the effect of trehalose on stability of refolded IFNβ-1b (interferon beta-1b). An intermediate, showing native-like secondary structure is possibly formed during refolding process of IFNβ-1b. Although the refolded protein showed high biological activity, the mathematical data demonstrated a flexible and mid-stable structure, possibly due to its non-glycosylated form. In the presence of 1.5M of trehalose an increase of 16°C was observed in the T m of the refolded protein from the initial of 35° C. The stability of IFNβ-1b was possibly improved by preferential exclusion of trehalose and formation of a dense hydration shell around the protein surface. Lower amounts of helical structures (16%) were detected in protein solutions without trehalose. In the presence of trehalose the active structure of IFNβ-1b was probably preserved by formation of a metastable structure which subsequently eased post-refolding processes of the protein. [Copyright &y& Elsevier]

Abstract: Ag–Ni alloy films were electrodeposited from thiourea-based acidic solutions. Electrochemical studies confirmed the strong polarization of Ag deposition due to the strong complexation of Ag+ with thiourea, bringing the onset of Ag and Ni deposition closer, potentially favoring alloy formation. The as-deposited films were very fine grained (less than 20nm) and consisted of various phases: a supersaturated solid solution of Ni in Ag and a Ni-rich nanocrystalline or amorphous phase, preferentially formed at grain boundaries. Ag-rich films were smooth, while a higher Ni content resulted in increasingly rough and porous films. Decomposition of the metastable phase and precipitation of the pure elemental phases occurred upon thermal annealing at 600°C. Reduction of thiourea induced by Ni deposition led to sulfur incorporation in the films, up to 20at.%. [Copyright &y& Elsevier]