Entire Composition Research Articles

Structural characterisation of Cu-Zr thin film combinatorial libraries with synchrotron radiation at the limit of crystallinity

We report for the first-time combinatorial synthesis of thin film metallic glass libraries via magnetron co-sputtering at the limit of crystallinity. Special care was taken to prepare extremely pure CuZr films (1–2 µm thickness) with large compositional gradients (Cu18.2Zr81.8 to Cu74.8Zr25.2) on X-ray transparent polymer substrates in high-vacuum conditions. Combined mapping of atomic structure (synchrotron radiation) and chemical composition (X-ray fluorescence spectroscopy) revealed that over the entire composition range, covering multiple renowned glass formers, two phases are present in the film. Our high-resolution Synchrotron approach identified the two phases as: untextured amorphous Cu51Zr14 (cluster size 1.3 nm) and textured, nanocrystalline α-Zr (grain size 1–5 nm). Real space HR-STEM analyses of a representative composition substantiate our XRD results. Determined cluster and grain sizes are below the resolution limit of conventional laboratory-scale X-ray diffractometers. The presented phase mixture is not permitted in the Cu-Zr phase diagram and contrary to existing literature. The phase ratio follows a linear trend with amorphous films on the Cu-rich side and increasing amounts of α-Zr with increasing Zr content. While cluster size and composition of the amorphous phase remain constant thorough the compositional gradient, crystallite size and texture of the nanocrystalline α-Zr change as a function of Zr content.

Novel Biomarkers of Health and Degeneration in Human Intervertebral Discs: In-depth Proteomic Analysis of Collagen Framework of Fetal, Healthy, Scoliotic, Degenerate, and Herniated Discs.

Profiling proteins expressed in the nucleus pulposus (NP) of intervertebral discs (IVDs) in five different biological states. To evaluate the molecular complexity of the collagen (COL) framework and its role in the health and disease of human IVDs. Changes in COL composition have been linked to degenerative disk disease (DDD). Despite the fact that humans have 28 different types of COLs, most of the literature focuses solely on COL-1 and COL-2. This study used high-end proteomic technology to examine the entire COL composition of the human IVD across fetal (developmental-FD), normal (healthy-ND), scoliotic (early degeneration-SD), herniated (degenerate-DH), and degenerated (DD) disk phenotypes. Forty NP tissues were snap-frozen in liquid nitrogen (-196°C) immediately before being subjected to proteomic and bioinformatic analyses from five different disk phenotypes (eight each). Tandem mass spectrometric analysis revealed a total of 1,050 proteins in FDs, 1,809 in ND, 1,487 in SD, 1,859 in DH, and 1,538 in the DD group. Of 28 major collagens reported in the human body, this study identified 24 different collagens with 34 subtypes in NP. Fibril-forming collagens (COL-1, 2, and 11A1) and fibril-associated collagens with interrupted triple helices (COL-9A1, 12A1, and 14A1) were abundantly expressed in FDs, representing their role in the development of NP. Multiplexin (COL-15), a hybrid proteoglycan-collagen molecule, was discovered only in FDs. Degeneration was associated with COL2A1 downregulation and COL-10A1 upregulation. COL10 was discovered to be a new biomarker for disk degeneration. Besides COL-1 and 2, other important COLs (6, 9, 11, 12, 14, 15) with anabolic potential and abundant expression in the fetal phenotype could be investigated for tissue engineering and novel DDD therapy.

NIR emission spectral engineering in NaSc(Si,Ge)2O6: Cr3+ solid-solution phosphors via crystal field regulation

A series of NIR-emitting NaSc(Si2-xGex)O6: Cr3+ phosphors have been synthesized by a solid-state reaction. NaSc(Si2-xGex)O6 is found to retain the same monoclinic crystal structure and form a solid-solution within the entire composition range. When excited by 470 nm blue light, the phosphors emit broadband and tunable emission with a peak maximum shifting from 850 nm to 910 nm, depending on the Si/Ge ratio. Fluorescence decay curves and temperature dependent photoluminescence were also discussed. With increasing Ge4+ content, the red-shift behaviors can be ascribed to the weakened crystal field splitting from lattice expansion, and the emission intensities first increased, then decreased, and finally increased to the maximum at x = 0.2. As discussed, optimal NaSc(Si1.8Ge0.2)O6: Cr3+ phosphor have potential applications as a source for NIR lighting.

Heats of formation and stress–strain relationship of Fe–Cr solid solutions from a constructed Fe–Cr potential

A new Fe–Cr interatomic potential is constructed under the framework of the embedded-atom method and has better performances in predicting heats of formation and stress–strain relationship of Fe–Cr solid solutions than the Fe–Cr potentials already published in the literature. Based on the constructed Fe–Cr potential, molecular dynamics simulation reveals that the heats of formation of BCC Fe–Cr solid solutions at 1600 K are positive within the entire composition range, and the calculated values are in good agreement with corresponding experimental measurements in the literature. In addition, it is also found that the tensile strengths of BCC Fe–Cr solid solutions increase with the increase of the Cr composition, and that BCC Fe–Cr solid solutions are less ductile with smaller critical strains than both Fe and Cr. The simulated results are discussed and compared with the corresponding experimental and calculated evidence in the literature to validate the relevance of the newly constructed Fe–Cr potential.

Densities and excess volumes of binary and ternary mixtures of N, N-dimethyl sulfoxide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone at T = (293.15, 313.15)K and atmospheric pressure

Densities of binary liquid mixtures of N,N-dimethyl acetamide (DMA) + dimethyl sulfoxide (DMSO), DMSO + N - methyl-2-pyrrolidone (NMP), and DMA + NMP were measured over the entire composition range in the temperatures of 293.15 K and 313.15 K at atmospheric pressure. Based on this measurements, density deviations, Δρ, and excess molar volumes, V E , of binary mixtures were calculated and the same were fitted by Redlich-Kister equation. Binary adjustable parameters were obtained using Linear Least Squares Regression (Microsoft Excel 2016). The variations of derivative properties with temperature and composition were discussed. The densities of ternary mixtures DMSO + DMA + NMP were measured at 293.15 K and 313.15 K. According to experimental data, diagrams of density isolines at both temperature, density changes and excess molar volume at 293.15 K are constructed.

Electrical resistivity evolution in electrodeposited Ru and Ru-Co nanowires

• Propose a strategy to reduce electrical resistivity and complexity of current interconnect structure in ICs. • Emulate a semiconductor metallization environment employing porous nano-templates. • Design nanoscale Ru and Ru-Co structures by electrodeposition. • Uncover electrical properties of Ru-based nanowires and microstructural evolution. Nanoscale ruthenium (Ru)-based materials are promising replacements for existing multilayered Cu interconnects in integrated circuits. However, it is not easy to apply the results of previously reported studies directly to the electrochemical damascene process because the previous studies have mainly focused on thin films by dry deposition. Here, we report the electrical resistivity and microstructure of electrodeposited Ru nanowires. We estimate that the resistivity value of a 10 nm diameter Ru nanowire to be 71.6 μΩ cm after analyzing the resistivity values of individual nanowires with various diameters. Furthermore, we investigate the electrical properties of Ru x Co 1- x nanowires where x is 0.04–0.99 at.% as possible replacements of the current TaN barrier structures. Over the entire composition range, the resistivity values of alloys are much lower than that of the conventional TaN. Additionally, Ru and Ru-alloy nanowires surrounded by dielectric silica are thermally stable after 450 °C heat treatment. Therefore, the nanoscale Ru and Ru-Co alloys possessing low resistivity values can be candidates for the interconnect and barrier materials, respectively.

Excess Thermodynamic Properties of Ethyl Acetate with Primary Alcohols At 303.15 K

Densities (ρ) and sound velocity (u) for the binary mixtures of ethyl acetate with 1-methanol, 1- ethanol, 1- propanol, 1- butanol, 1-hexanol and 1-octanol were measured over the entire composition range at 303.15 K. From these data, excess molar volume (VE), isentropic compressibility (Ks ) and deviation in isentropic compressibility (ΔKs ) have been calculated with the Redlich-Kister Polynomial equation. The experimental data were discussed in terms of intermolecular interactions between component molecules.

Atomistic prediction on the composition- and configuration-dependent bandgap of Ga(As,Sb) using cluster expansion and ab initio thermodynamics

The composition- and configuration-dependent bandgaps of pseudobinary Ga(As,Sb) are examined by the cluster expansion method and statistical thermodynamics based on density functional theory. The bandgaps and energetic stability of 330,000 configurations in the entire composition range show a consistent inverse relationship, in that a configuration with lower energy has a higher bandgap for a given composition. This inverse relation can be deduced from the opposite signs of effective cluster interaction coefficients for bandgap and energy, and can be quantified by the correlations of properties with short-range order parameters. The bandgap of GaAs0.5Sb0.5 varies from 0.02 to 0.93 eV depending on the atomic configuration, which suggests another tremendous chance to tune the bandgap by the configuration control. The average bandgap of a certain composition, calculated by the ab initio thermodynamics, decreases with increasing temperature. The calculated average bandgap shows feasible agreement with the experimental bandgap, reproducing the bandgap bowing.

Volumetric and Acoustic Properties of Binary and Ternary Mixtures of Butanol Isomers with Gasoline Surrogate Compounds

Substituting butanol, a renewable fuel for internal combustion engine, as the gasoline blend against the conventionally used ethanol requires the knowledge of their thermophysical properties as these properties decide the fuel injection system, flame propagation, and combustion process in a compression ignition engine. Butanols offer higher energy density and lower tendency to absorb moisture. To offer proof of concept of the influence of temperature and composition of various organic solvents in the isomers of butanol, herein, we had experimentally measured the values of densities (ρ) and speeds of sound (u) of butanol isomers with o-xylene, toluene, and 2,2,4-trimethylpentane at different temperatures (T = 298.15 and 308.15 K) and at 101.3 kPa pressure and over the entire composition range. Measured data have been used to calculate the thermodynamic properties, namely, excess molar volumes VmE and excess molar isentropic compressibilities Ks, mE. The behavior and influence of the temperature and proportion of butanol isomers on measured and calculated properties were studied. Experimental VmE data have been fitted to the Redlich–Kister polynomial equation, and standard errors in prediction were determined. Densities of the binary system are predicted by the PC-SAFT equation of state. We further have used the Prigogine–Flory–Patterson (PFP) theory to predict VmE of the studied systems. Results of predicted and experimentally determined VmE over the entire range of proportion of butanols are compared. Influence of isentropic compressibility on the resulting fuel’s combustion characteristics has been cursorily discussed.

Density, speed of sound, refractive index of binary mixtures containing 2-ethoxyethanol and some alcohols: Measurement and correlation

The aim of this research to investigate thermophysical properties of alkoxyethanols with alcohols, including densities, speeds of sound, and refractive index of five binary mixtures constituted by 2-ethoxyethanol (2EE) + methanol, or ethanol, or propan-1-ol, or propan-2-ol, or butan-2-ol, that have been measured at the temperatures: (293.15, 303.15, 313.15 and 323.15) K, over the entire composition range and at pressure of p = 0.1 MPa. The Cubic Plus Association equation of state (CPA-EOS) has been used to correlate the measured properties. From the measured data, excess/derived properties: excess molar volume, isentropic compressibility, deviation in isentropic compressibility and deviation in refractive index were calculated and correlated using the Redlich − Kister equation. The results obtained from the work have been discussed in terms of the nature of molecular interactions between the components of the mixture.

Investigation of solute-solvent interactions between 2-butoxyethanol and substituted ketones by volumetric, acoustic and FTIR studies at T=(303.15–318.15) K

The densities (ρ) and speeds of sound (u) were measured for the binary mixtures of 2-butoxyethanol (BE) with methyl ethyl ketone (MEK), methyl propyl ketone (MPK), di-ethyl ketone (DEK) and methyl isobutyl ketone (MIBK) mixtures at temperatures (303.15–318.15) K and pressure (P = 0.1 MPa) over the entire composition range. The experimental data were used to derive the excess molar volume (VmE), excess isentropic compressibility (κSE) and excess speed of sound (uE). The calculated excess parameters have been correlated by Redlich-Kister equation. These results have been analysed by different theoretical models such as PFP, CFT and FLT. The effect of alkyl chain length of ketones on the excess properties has been discussed in terms of disruption of H-bonding and dipole–dipole interaction between the components of the mixtures. The thermodynamic results of the present investigation have been correlated with FTIR spectral studies and obtained a good agreement.

Densities and viscosities of mixtures containing water, methanol and ethanol

The experimental densities and viscosities are reported in this paper for the binary mixtures: water + methanol, water + ethanol and methanol + ethanol over the entire composition range at 293.15 K and atmospheric pressure. From these experimental data, the excess molar volumes, V E, and deviations in viscosity, Δη, were derived and fitted to the Redlich–Kister polynomial to determine the adjustable fitting parameters and standard deviations. The variation of excess and deviation properties with composition has been interpreted in terms of the molecular interactions between the components of the mixtures and structural effects. Additionally, various correlation models were applied to estimate the viscosities of the mixtures to test their validity for the mixtures being studied.

Correlative image learning of chemo-mechanics in phase-transforming solids.

Constitutive laws underlie most physical processes in nature. However, learning such equations in heterogeneous solids (for example, due to phase separation) is challenging. One such relationship is between composition and eigenstrain, which governs the chemo-mechanical expansion in solids. Here we developed a generalizable, physically constrained image-learning framework to algorithmically learn the chemo-mechanical constitutive law at the nanoscale from correlative four-dimensional scanning transmission electron microscopy and X-ray spectro-ptychography images. We demonstrated this approach on LiXFePO4, a technologically relevant battery positive electrode material. We uncovered the functional form of the composition-eigenstrain relation in this two-phase binary solid across the entire composition range (0 ≤ X ≤ 1), including inside the thermodynamically unstable miscibility gap. The learned relation directly validates Vegard's law of linear response at the nanoscale. Our physics-constrained data-driven approach directly visualizes the residual strain field (by removing the compositional and coherency strain), which is otherwise impossible to quantify. Heterogeneities in the residual strain arise from misfit dislocations and were independently verified by X-ray diffraction line profile analysis. Our work provides the means to simultaneously quantify chemical expansion, coherency strain and dislocations in battery electrodes, which has implications on rate capabilities and lifetime. Broadly, this work also highlights the potential of integrating correlative microscopy and image learning for extracting material properties and physics.

Thermodynamic modeling of the Ni–S system

Abstract A thorough review and critical evaluation of phase equilibria and thermodynamic data of the nickel – sulfur binary system at 1 bar pressure has been made over the entire composition range for temperatures from 25°C to above the liquidus. The Gibbs energies of nine phases have been modeled, and optimized model parameters have been obtained which reproduce all data simultaneously within experimental error limits. For the liquid phase, the recently extended modified quasichemical model is applied. Two-sublattice models within the framework of the Compound Energy Formalism are used for the high-temperature heazlewoodite and monosulfide pyrrhotite solutions. The Gibbs energies of six stoichiometric compounds are also modeled.

Aramid nanofiber-reinforced multilayer electromagnetic-interference (EMI) shielding composites with high interfacial durability

Structural composites for electric vehicles should have lightweight, mechanically strong, efficient electromagnetic shielding. Although thermoplastic composite material plays a structural role and aluminum thin film (Al foil) plays the role of electromagnetic wave shielding, poor interfacial adhesion and tear-resistance of Al foil need to be overcome. In this work, we demonstrated a novel, high-performance EMI-shielding multilayer structure based on an aluminum thin film (Al), glass fabric (GF), carbon fiber-reinforced thermoplastic (CFT), and thermoplastic adhesive. In particular, the interfacial adhesion at the mechanically weak interface has been significantly improved by a factor of 1.15 via the application of an aramid nanofiber-embedded (ANF) thermoplastic interlayer. We found that the distribution and entanglement of aramid nanofibers in the ANF adhesive layer precisely determine the mechanical properties of the entire structural composite. Efficient EMI shielding performance (an average of 94 dB at 0.2–1.0 GHz) of structural EMI shielding composites was possible using a uniform aramid nanofiber layer.

Activity measurements of Ga in liquid Ga–Tl alloys by EMF method with zirconia solid electrolyte

Abstract Electromotive force measurements (EMF) of an electrochemical cell with zirconia as solid electrolyte were performed to determine the Ga activity from 973 to 1273 K in the entire composition range of liquid Ga–Tl alloys. In the whole concentration range, the activity of Ga shows large positive deviations from ideality, and the activity of Tl which is derived by the Gibbs–Duhem equation shows also positive deviation from ideality. The parameters of the Redlich – Kister equation for excess Gibbs energies of mixing are determined from the results obtained in this study which were compared with Chou’s model calculation.

Band Alignment of Al2O3 on α-(AlxGa1-x)2O3

X Ray Photoelectron Spectroscopy was used to measure valence band offsets for Al2O3 deposited by Atomic Layer Deposition on α-(AlxGa1-x)2O3 alloys over a wide range of Al contents, x, from 0.26–0.74, corresponding to a bandgap range from 5.8–7 eV. These alloys were grown by Pulsed Laser Deposition. The band alignments were type I (nested) at x <0.5, with valence band offsets 0.13 eV for x = 0.26 and x = 0.46. At higher Al contents, the band alignment was a staggered alignment, with valence band offsets of − 0.07 eV for x = 0.58 and −0.17 for x = 0.74, ie. negative valence band offsets in both cases. The conduction band offsets are also small at these high Al contents, being only 0.07 eV at x = 0.74. The wide bandgap of the α-(AlxGa1-x)2O3 alloys makes it difficult to find dielectrics with nested band alignments over the entire composition range.

Volumetric properties of binary mixtures of glycerol + alkanols (C1-C4): Experimental study and application of the Peng–Robinson–Stryjek–Vera equation of state

Volumetric properties for binary mixtures of (glycerol + methanol, or + ethanol, or + 1-propanol, or + 2-propanol, or + 1-butanol) have been determined as a function of composition using experimental data of density at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K and p = 92.3 kPa. The density measurements have been determined by using a vibrating-tube densimeter. The density values enabled the determination of the thermal expansion coefficient and the excess molar volume. The values of excess molar volume were correlated by a Redlich-Kister polynomial and by the Peng-Robinson-Stryjek-Vera equation of state (PRSV EOS). These values were also used in the estimation of the partial molar volumes, excess partial molar volumes and apparent molar volumes. Three different methods were used to determine the partial molar volumes at infinite dilution. For all studied systems, the values of excess molar volumes were negative over the entire composition range and suggest predominance of chemical and structural effects.

Probing the ion-dipole interactions between the imidazolium-based ionic liquids and polyethylene glycol 200 using excess thermodynamic and spectroscopy studies

The use of volatile organic compounds in industrial applications has generally been considered as detrimental to the environment and been a contributor to unsustainable activity. Ionic liquids (ILs) are generally considered as “green” and ecologically friendly solvents compared to volatile organic solvents. In the application of ILs in various processes, they are typically mixed with other solvents in order to modify their physicochemical properties. Thus, the focus in the present study on the interactions between ILs and polymer via thermophysical properties together with FT-IR analysis. In this study, density (ρ), viscosity (η), speeds of sound (u), and refractive index (nD) of the binary mixtures of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM+PF6-), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM+BF4-) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM+BF4-) with polyethylene glycol 200 (PEG200) were measured at (293.15, 303.15, 313.15, 323.15 and 333.15) K and at p = 0.1 MPa. Excess thermodynamic properties: excess molar volume (VE), excess isentropic compressibility (KsE), excess viscosity (ηE), excess refractive index (nDE) and excess thermal expansion coefficient (αPE) were calculated from the thermophysical properties for the new systems studied. Excess thermodynamic properties were best correlated using the Redlich-Kister polynomial equation. Excess thermodynamic properties such as excess molar volume (VE), excess isentropic compressibility (KsE), and excess thermal expansion coefficient (αPE), displayed negative deviations, while excess viscosity (ηE) and excess refractive index (nDE) exhibited positive deviations throughout the entire composition range for the new systems. In addition, FT-IR spectroscopy was further utilized to confirm the presence of ion–dipole interactions/hydrogen bonding between the molecules of ILs and PEG200. The results from FT-IR spectra support the results obtained from excess thermodynamic properties. The results from both excess thermodynamic properties and FT-IR spectroscopy analysis confirmed the presence of ion–dipole interactions/hydrogen bonding. The strength of the ion–dipole interactions formed between molecules of PEG200 and ions of ILs follows the order: EMIM+BF4- >BMIM+PF6- > BMIM+BF4-. This study of the ILs + PEG200 binary mixtures contributes to the knowledge of physicochemical properties of these mixtures which can be utilized in specific applications such polymeric electrolytes in different electrochemical devices.

Thermodynamic study of the aqueous pseudo-binary mixtures of betaine-based deep eutectic solvents at T = (293.15 to 313.15) K

ABSTRACT This work investigates physicochemical properties of betaine/propylene glycol (Bet/PG) and betaine/ethylene glycol (Bet/EG) DESs in water by measuring their densities in neat state and aqueous mixtures over the entire composition range at T = (288.15–318.15) K under atmospheric pressure (≈ 85 kPa). The obtained values of density were used to compute the excess molar volumes (), molar volume (V m), apparent molar volume (), limiting apparent molar expansibility () and the isobaric thermal expansion coefficient (). The solute-solvent interactions in the investigated solutions are evaluated on the basis of these important physicochemical properties. The results indicated that two studied DESs act as a structure-making solute in water over the whole temperature range using Hepler’s constant. Finally, the experimental densities were correlated with some models including Jouyban-Acree, Jouyban-Acree-van’t Hoff, modified Jouyban-Acree-van’t Hoff, Redlich-Kister and Emmerling. The Redlich-Kister expression and Jouyban-Acree model were also used for representation of values.