On the Solubilities and Rates of Solution of Gases in Liquid Methane
Solubilities of several gases in liquid methane and liquefied natural gas
Evans, Albert, Jr.↗
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Sugar extraction and ionic liquid recycling using alkaline solutions
The present invention provides a method for obtaining a monosaccharide from a lignocellulosic material in a form suitable for use as a carbon source in a reaction. In some embodiments, the monosaccharide is in a form suitable for use in a fermentation reaction, e.g., to produce an alcohol such as ethanol.
Sun, Ning↗
Rechargeable-Liquid Fuel Cells with a Novel Recharging Method: Exploratory Results with IPA and V II /V III Solutions
Rechargeable-liquid fuel cells (RLFCs) have the potential to be utilized in a wide variety of applications, if the performance of RLFCs can be substantially improved. Two of the major historical barriers have been the relatively poor performance of RLFCs compared to conventional polymer electrolyte fuel cells operating on hydrogen and the irreversibility of the oxygen electrode. This work demonstrates a new recharging concept and improved liquid-electrode designs, which help address both of these issues. These two concepts are demonstrated using two different types of rechargeable liquids: 1) an alcohol (isopropanol) that is reversibility dehydrogenated to the corresponding ketone (acetone), and 2) a flow-battery vanadium electrolyte (V II /V III dissolved in H 2 SO 4 ). The liquid electrodes utilize interdigitated flow fields, which enable relatively good power densities for a RLFC during discharge with air: 0.14 W/cm 2 at 0.6 V with 2 M IPA and 0.42 W/cm 2 at 0.7 V with 1.5 M V II /V III . It is also shown that the liquids can be efficiently recharged using the same cell that was used for the discharge, by supplying hydrogen to the gas electrode to generate protons via the hydrogen-oxidation reaction instead of splitting water, which requires a different catalyst or a bidirectional catalyst.
36 MATERIALS SCIENCE↗
Liquid-to-gas transfer of sodium in a liquid anode glow discharge
Solute transfer from the liquid to the gas phase in plasmas has been widely used in analytical chemistry often focused on liquid cathode discharges. In this study, we report on time-resolved absolute density measurements of sodium in a glow discharge plasma with a NaCl solution anode using two-photon absorption laser induced fluorescence. The averaged maximum sodium density is found to be similar to the electron density in the discharge consistent with plasma-induced vapor generation. Random sodium flashes were also observed extending into the plasma afterglow and are attributed to sodium particles falling back on the liquid surface. Cataphoresis can explain the location of the maximum sodium density near the cathode side of the electrode gap rather than near the liquid anode region.
chemical vapor generation↗
Freezing Behavior of Stratospheric Sulfate Aerosols Inferred from Trajectory Studies
Temperature histories based on 10-day back growth trajectories for six ER-2 flights during AASE I (1989) and AAOE (1987) are presented. These trajectories along with the properties of the observed PSC (polar stratospheric cloud) particles are used here to infer the physical state of the pre-existing sulfuric acid aerosols. Of all the ER-2 flights described here, only the PSCs observed on the flights of January 24 and 25, 1989 are consistent with the thermodynamics of liquid ternary solutions of H2SO4/HNO3/H2O Ib PSCs). For these two days, back trajectories indicate that the air mass was exposed to SAT (sulfuric acid tetrahydrate) melting temperatures about 24 hours prior to being sampled by the ER-2. For the remaining ER-2 flights (January, 16, 19, and 20 for the AASE I campaign and August 17 for the AAOE campaign), the observed PSCs were probably composed of amorphous solid solutions of HNO3 and H2O (Type Ic PSCs). Formation of such Type Ic PSCs requires the presence of solid H2SO4 aerosols since liquid aerosols yield ternary solutions. The 10-day back trajectories of these flights indicate that the air mass was not exposed to SAT melting temperatures during the past week and had experienced cooling/warming cycles prior to being sampled by the ER-2. These temperature histories, recent laboratory measurements and the properties of glassy solids suggest that stratospheric H2SO4 aerosols may undergo a phase transition to SAT upon warming at approximately 198 K after going through a cooling cycle to about 194 K or lower.
Tabazadeh, A.↗
Condensation of Self-Assembled Lyotropic Chromonic Liquid Crystal Sunset Yellow in Aqueous Solutions Crowded with Polyethylene Glycol and Doped with Salt
We use optical and fluorescence microscopy, densitometry, cryo-transmission electron microscopy (cryo-TEM), spectroscopy, and synchrotron X-ray scattering to study the phase behavior of the reversible self-assembled chromonic aggregates of an anionic dye Sunset Yellow (SSY) in aqueous solutions crowded with an electrically neutral polymer polyethylene glycol (PEG) and doped with the salt NaCl. PEG causes the isotropic SSY solutions to condense into a liquid-crystalline region with a high concentration of SSY aggregates, coexisting with a PEG-rich isotropic (I) region. PEG added to the homogeneous nematic (N) phase causes separation into the coexisting N and I domains; the SSY concentration in the N domains is higher than the original concentration of PEG-free N phase. Finally, addition of PEG to the highly concentrated homogeneous N phase causes separation into the coexisting columnar hexagonal (C) phase and I phase. This behavior can be qualitatively explained by the depletion (excluded volume) effects that act at two different levels: at the level of aggregate assembly from monomers and short aggregates and at the level of interaggregate packing. We also show a strong effect of a monovalent salt NaCl on phase diagrams that is different for high and low concentrations of SSY. Upon the addition of salt, dilute I solutions of SSY show appearance of the condensed N domains, but the highly concentrated C phase transforms into a coexisting I and N domains. We suggest that the salt-induced screening of electric charges at the surface of chromonic aggregates leads to two different effects: (a) increase of the scission energy and the contour length of aggregates and (b) decrease of the persistence length of SSY aggregates.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
A phonon thermodynamics approach of gold nanofluids synthesized in solution plasma
The phonon thermodynamics theory for liquids was applied to explain the thermal characteristics of gold nanofluids synthesized by a simple, one-step, and chemical-free method using an electrical discharge in a liquid environment termed solution plasma process. The specific heat capacity of nanofluids was measured with a differential scanning calorimeter using the ratio between the differential heat flow rate and the heating rate. The decrease of the specific heat capacity with 10% of gold nanofluids relative to water was explained by the decrease of Frenkel relaxation time with 22%, considering a solid-like state model of liquids.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Visualizing Solution Structure at Solid-Liquid Interfaces using Three-Dimensional Fast Force Mapping
Amongst the challenges for a variety of research fields are the visualization of solid-liquid interfaces and understanding how they are affected by the solution conditions such as ion concentrations, pH, ligands, and trace additives, as well as the underlying crystallography and chemistry. Here, in this context, three-dimensional fast force mapping (3D FFM) has emerged as a promising tool for investigating solution structure at interfaces. This capability is based on atomic force microscopy (AFM) and allows the direct visualization of interfacial regions in three spatial dimensions with sub-nanometer resolution. Here we provide a detailed description of the experimental protocol for acquiring 3D FFM data. The main considerations for optimizing the operating parameters depending on the sample and application are discussed. Moreover, the basic methods for data processing and analysis are discussed, including the transformation of the measured instrument observables into tip-sample force maps that can be linked to the local solution structure. Finally, we shed light on some of the outstanding questions related to 3D FFM data interpretation and how this technique can become a central tool in the repertoire of surface science.
Nakouzi, Elias↗
Elucidating the Role of Halides and Iron during Radiolysis-Driven Oxidative Etching of Gold Nanocrystals Using Liquid Cell Transmission Electron Microscopy and Pulse Radiolysis
Graphene liquid cell transmission electron microscopy (TEM) has enabled the observation of a variety of nanoscale transformations. Yet understanding the chemistry of the liquid cell solution and its impact on the observed transformations remains an important step toward translating insights from liquid cell TEM to benchtop chemistry. Gold nanocrystal etching can be used as a model system to probe the reactivity of the solution. FeCl 3 has been widely used to promote gold oxidation in bulk and liquid cell TEM studies, but the roles of the halide and iron species have not been fully elucidated. In this work, we observed the etching trajectories of gold nanocrystals in different iron halide solutions. We observed an increase in gold nanocrystal etch rate going from Cl - - to Br - - to I - -containing solutions. Furthermore, this is consistent with a mechanism in which the dominant role of halides is as complexation agents for oxidized gold species. Additionally, the mechanism through which FeCl 3 induces etching in liquid cell TEM remains unclear. Ground-state bleaching of the Fe(III) absorption band observed through pulse radiolysis indicates that iron may react with Cl 2 · - radicals to form an oxidized transient species under irradiation. Complete active space self-consistent field (CASSCF) calculations indicate that the FeCl 3 complex is oxidized to an Fe species with an OH radical ligand. Together our data indicate that an oxidized Fe species may be the active oxidant, while halides modulate the etch rate by tuning the reduction potential of gold nanocrystals.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Twin solution calorimeter determines heats of formation of alloys at high temperatures
Calvert-type, twin liquid metal solution calorimeter determines the heats of formation of transition metal alloys at high temperatures. The twin differential calorimeter measures the small heat effects generated over extended periods of time, has maximum operating temperature of 1073 degrees K and an automatic data recording system.
Darby, J. B., Jr.↗
Mathematical Analysis of the Solidification Behavior of Plain Steel Based on Solute- and Heat-Transfer Equations in the Liquid–Solid Zone
An analytical approximate solution to non-linear solute- and heat-transfer equations in the unsteady-state mushy zone of Fe-C plain steel has been obtained, assuming a linear relationship between the solid fraction and the temperature of the mushy zone. The heat transfer equations for both the solid and liquid zone along with the boundary conditions have been linked with the equations to solve the whole equations. The model predictions (e.g., the solidification constants and the effective partition ratio) agree with the generally accepted values and with a separately performed numerical analysis. The solidus temperature predicted by the model is in the intermediate range of the reported formulas. The model and Neuman’s solution are consistent in the low carbon range. A conventional numerical heat analysis (i.e., an equivalent specific heat method using the solidus temperature predicted by the model) is consistent with the model predictions for Fe-C plain steels. The model presented herein simplifies the computations to solve the solute- and heat-transfer simultaneous equations while searching for a solidus temperature as a part of the solution. Thus, this model can reduce the complexity of analyses considering the heat- and solute-transfer phenomena in the mushy zone.
36 MATERIALS SCIENCE↗
Quantum cluster equilibrium model of N-methylformamide–water binary mixtures
The established quantum cluster equilibrium (QCE) approach is refined and applied to N-methylformamide (NMF) and its aqueous solution. The QCE method is split into two iterative cycles: one which converges to the liquid phase solution of the QCE equations and another which yields the gas phase. By comparing Gibbs energies, the thermodynamically stable phase at a given temperature and pressure is then chosen. The new methodology avoids metastable solutions and allows a different treatment of the mean-field interactions within the gas and liquid phases. These changes are of crucial importance for the treatment of binary mixtures. For the first time in a QCE study, the cis-trans-isomerism of a species (NMF) is explicitly considered. Cluster geometries and frequencies are calculated using density functional theory (DFT) and complementary coupled cluster single point energies are used to benchmark the DFT results. Independent of the selected quantum-chemical method, a large set of clusters is required for an accurate thermodynamic description of the binary mixture. The liquid phase of neat NMF is found to be dominated by the cyclic trans-NMF pentamer, which can be interpreted as a linear trimer that is stabilized by explicit solvation of two further NMF molecules. This cluster reflects the known hydrogen bond network preferences of neat NMF.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
HCl Vapour Pressures and Reaction Probabilities for ClONO2 + HCl on Liquid H2SO4-HNO3-HCl-H20 Solutions
Henry's Law solubility constants for HCl have been measured for liquid H2SO4-HNO3-HCl-H2O solutions; the results are in good agreement with predictions from published semiempirical models. The ClONO2 + HCl reaction on the surfaces of such solutions with compositions simulating those of stratospheric aerosols has been investigated; as the composition changes following the temperature drop characteristic of the high-latitude stratosphere the reaction probability gamma increases rapidly. Furthermore, the gamma values remain essentially unchanged when HN03 uptake is neglected; the controlling factor appears to be the solubility of HCl. These results corroborate our earlier suggestion that supercooled liquid sulfate aerosols promote chlorine activation at low temperatures as efficiently as solid polar stratospheric cloud particles.
Elrod, M. J.↗
Effect of the annealing temperature and ion-beam bombardment on the properties of solution-derived HfYGaO films as liquid crystal alignment layers
Hafnium yttrium gallium oxide (HfYGaO) films were applied to liquid crystal displays (LCDs) as liquid crystal (LC) alignment layers, replacing conventional polyimide (PI) layers. The HfYGaO alignment layers were prepared by fabricating solution-processed HfYGaO films, annealing them, and treating them with ion-beam (IB) irradiation. The authors studied the effects of annealing temperature and IB irradiation of the solution-derived HfYGaO films on the orientation of LC molecules. The LC molecules on the solution-derived HfYGaO films were homogeneously and uniformly aligned by IB irradiation, irrespective of the annealing temperature. Atomic force microscopy analyses revealed that the surface reformation of the HfYGaO films induced by IB irradiation strengthened the van der Waals force between the LC molecules and the HfYGaO films, leading to uniform LC alignment. Enhanced electro-optical characteristics were observed in the twisted-nematic (TN) LCDs based on IB-irradiated HfYGaO films compared with those of TN-LCDs based on PI layers, demonstrating the high application potential of the proposed solution-derived HfYGaO films as LC alignment layers.
42 ENGINEERING↗
Radiation-induced preparation of antimony from solutions of antimony/III/ chloride in organic liquids
Electron irradiation induced separation of Sb from SbCl3 solutions in anhydrous alcohols, ethers, ketones, acids, ethers, and aromatic hydrocarbons
Marsik, S. J.↗
Resolving amorphous solid-liquid interfaces by atomic force microscopy
Recent advancements in liquid atomic force microscopy make it an ideal technique for probing the structure of solid-liquid interfaces. Here, we present a structural study of a two-dimensional amorphous silica bilayer immersed in an aqueous solution utilizing liquid atomic force microscopy with sub-nanometer resolution. Structures show good agreement with atomically resolved ultra-high vacuum scanning tunneling microscopy images obtained on the same sample system, owing to the structural stability of the silica bilayer and the imaging clarity from the two-dimensional sample system. Pair distance histograms of ring center positions are utilized to develop quantitative metrics for structural comparison, and the physical origin of pair distance histogram peaks is addressed by direct assessment of real space structures.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Containerless Techniques for in-situ X-Ray Measurements on Materials in Extreme Conditions
This article reviews containerless methods in the context of measuring materials in-situ using x-ray techniques. Non-contact processing enables high chemical purity to be achieved even at temperatures above 2000 °C. The absence of extrinsic heterogenous nucleation allows supercooling and supersaturation of liquids and solutions. In many cases new types of glass can be made, particularly from fragile liquids. Current methods for containerless processing are briefly reviewed. The application of scattering, spectroscopic and emerging x-ray techniques is described. Examples including measurements on molten metal oxides, molten metallic alloys and organic molecules are presented. The work is discussed in the broader context of combining structure and property data to predict how to make new applied materials.
36 MATERIALS SCIENCE↗