Surface Of Individual Particles Research Articles

Acoustic Emission in Zirconium Hydrogenation Process

Acoustic emission signals occurring during the interaction of zirconium metal samples with hydrogen, as well as changes occurring in hydrogenated samples and being sources of high-amplitude acoustic signals, have been studied. The hydrogenation of pieces of compact iodide zirconium with a size from 5 to 10 mm, chips obtained from compact iodide zirconium with a linear particle size from 2 to 3 mm and a thickness of 0.2 mm, a «large» powder of electrolytic zirconium of a fraction from 80 to 550 microns and a «small» powder of electrolytic zirconium with a particle size of less than 80 microns was carried out. It has been established that the source of high-amplitude acoustic signals in all cases is the cracking of zirconium particles at the macro level, which leads to the formation of extended cracks and fractures on the surface of individual particles, as well as to the grinding of original materials. Cracking and grinding are caused by deformation and internal stresses occurring in the samples due to an increase in the volume of the solid phase during hydrogenation. It is shown for the first time that the atomic ratio [H] / [Zr] in the solid phase, corresponding to the maximum amplitude of a acoustic emission signal, naturally increases in a series: pieces of compact iodide zirconium-chips of iodide zirconium-«large» powder of electrolytic zirconium-«small» powder of electrolytic zirconium, which is in good agreement with the results of previous studies similar studies on the hydrogenation of titanium metal samples.

Magnetic resonance imaging of trickle flow

AbstractTrickle bed reactors (TBR) are widely used in the chemical industries. These reactors involve gas and liquid flow through a catalyst‐packed bed. For optimal TBR performance, it is crucial to achieve a uniform distribution of gas and liquid among the catalyst particles. However, in multitubular reactors with slender tubes, flow maldistribution near the tube walls is a common issue. Therefore, a comprehensive understanding of local phase and flow distribution is essential for designing and operating reactors with slender tubes. This article employs Magnetic Resonance Imaging (MRI) to characterize the three‐dimensional distribution of the two‐phase trickle flow within a slender tube. Three quantities are characterized: gas‐liquid‐solid distribution, particle wetting efficiency, and the flow field. Structure and flow MRI images are processed to calculate these quantities. Additionally, a novel postprocessing technique is introduced to determine the liquid distribution over individual particle surfaces. This distribution is determined at several axial and radial positions.

Stabilizing Lattice Oxygen in Slightly Li-Enriched Nickel Oxide Cathodes Toward High-Energy Batteries

LiNiO2 (LNO, 100% Ni) is an old material first identified in the early 1990s (as a higher-capacity and lower-cost alternative to LiCoO2) but has yet to fulfill its potential. Despite intense research efforts for more than two decades, LNO still exhibits rapid capacity loss during cycling and poor thermal stability (1-3). The traditional LNO is generally prepared by solid-state reactions and recognized as Li-deficient Li1-yNi1+yO2 (4). Ex situ characterizations indicated that the performance degradation originates from the detrimental phase transition (layered to rock-salt structure) during electrochemical cycling (5-7), which is closely related to the lattice-oxygen release during charge (8, 9). To improve the performance of LNO, the structure is commonly modified by lattice doping or surface coating, which have led to improved cycle stability but at the cost of capacity loss (10). Meanwhile, these modification approaches failed to address the lattice oxygen instability, as the O2 release was still detected for the doped or surface-coated layered cathodes (11, 12).Here, we demonstrate an Li-enrichment strategy to produce a trigonal-structured layered Li-enriched LNO (Li1.04Ni0.96O2, LR-LNO) with a slight excess of Li to occupy the Ni sites, which is a possible phase according to the Li-Ni-O phase diagram but has never been experimentally synthesized (Figure 1). LR-LNO (Figure 1) enables a combination of a high specific energy density of 904 Wh kg-1, outstanding cyclability (~80% capacity retention after 400 cycles in full cells versus 35 cycles for LNO), and significantly enhanced thermal stability (>70 °C increase in thermal-runaway temperature over LNO).We further designed a double-tilt electrochemical liquid cell inside a transmission electron microscope (TEM) to track the local structural changes at the surface of individual particles during galvanostatic cycling (Figure 2), revealing the performance-enhancing mechanism behind the slight change in the material composition. Excess Li ions in the Ni layer promoted intralayer migration of Ni ions during delithiation in LR-LNO, generating vacancy clusters to trap the electrochemically oxidized molecular O2 in the near-surface lattice. Consequently, the oxygen redox reaction became highly reversible, and the detrimental layered-to-rock-salt phase transition are effectively inhibited, thus improving the structural reversibility of LR-LNO during cycling and the thermal stability.Our results provide a composition fine-tuning strategy to produce highly-reversible cathodes for high energy-density, low-cost and safe batteries. Beyond batteries, the double-tilt operando TEM technique will facilitate studies into complex phase transitions in a wide range of materials. Figure 1 Pristine structure and outstanding performance of LR-LNO References M. M. Thackeray, K. Amine, Layered Li–Ni–Mn–Co oxide cathodes. Nature Energy 6, 933-933 (2021). A. Manthiram, J. B. Goodenough, Layered lithium cobalt oxide cathodes. Nature Energy 6, 323-323 (2021). K. Turcheniuk, D. Bondarev, V. Singhal, G. Yushin, Ten years left to redesign lithium-ion batteries. Nature 559, 467-470 (2018). J.-H. Kim, K.-J. Park, S. J. Kim, C. S. Yoon, Y.-K. Sun, A method of increasing the energy density of layered Ni-rich Li[Ni1−2xCoxMnx]O2 cathodes (x = 0.05, 0.1, 0.2). Journal of Materials Chemistry A 7, 2694-2701 (2019). C. S. Yoon, D.-W. Jun, S.-T. Myung, Y.-K. Sun, Structural stability of LiNiO2 cycled above 4.2 V. ACS Energy Lett. 2, 1150-1155 (2017). D.-W. Jun, C. S. Yoon, U.-H. Kim, Y.-K. Sun, High-energy density core-shell structured Li[Ni0.95Co0.025Mn0.025]O2 cathode for lithium-ion batteries. Chem. Mater. 29, 5048-5052 (2017). C. S. Yoon, M. H. Choi, B. B. Lim, E. J. Lee, Y.-K. Sun, Review—high-capacity Li[Ni1-xCox/2Mnx/2]O2 (x = 0.1, 0.05, 0) cathodes for next-generation Li-ion battery. J. Electrochem. Soc. 162, A2483-A2489 (2015). N. Li et al., Unraveling the cationic and anionic redox reactions in a conventional layered oxide cathode. ACS Energy Lett. 4, 2836-2842 (2019). S. S. Zhang, Problems and their origins of Ni-rich layered oxide cathode materials. Energy Storage Materials 24, 247-254 (2020). M. Bianchini, M. Roca-Ayats, P. Hartmann, T. Brezesinski, J. Janek, There and back again-the journey of LiNiO2 as a cathode active material. Angew. Chem., Int. Ed. 58, 10434-10458 (2019). N. Li et al., Correlating the phase evolution and anionic redox in Co-Free Ni-Rich layered oxide cathodes. Nano Energy 78, (2020). F. Strauss et al., Li2ZrO3-Coated NCM622 for Application in Inorganic Solid-State Batteries: Role of Surface Carbonates in the Cycling Performance. ACS applied materials & interfaces 12, 57146-57154 (2020). Figure 1

Energy loss separation in NiFeMo compacts with smoothed powders according to Landgraf\u2019s and Bertotti\u2019s theories

This submitted paper presents the detailed description of the energy loss separation for dc and ac low-frequency magnetic fields of NiFeMo (supermalloy) compacted powder prepared by innovative method of smoothing the surfaces of individual particles. The positive impact of mechanical treatment method on domain wall displacement is explained on the basis of Landgraf approach for dc loss analysis, and the effective dimension for eddy current in ac magnetic field is explained according to Bertotti approach for core loss analysis.

Fluid-particle heat transfer in static assemblies: Effect of particle shape

The heat transfer in fluid flow through static assemblies of randomly distributed spheroids, including spheres, prolates, and oblates, is investigated using direct numerical simulation (DNS). Constant heat fluxes are imposed at individual particle surface by the Neumann boundary condition for temperature. The superficial Reynolds number (Re) and the solid volume fraction (φ) range from 2.5 to 200, and from 0.1 to 0.3, respectively. The simulation results for spheres and prolates agree well with the DNS data and correlations in literature and new correlations for prolates and oblates are proposed. With these results, the particle shape effect on the average Nusselt number (Nuavg) is described more comprehensively: At low φ (e.g., 0.1), the Nuavg for prolates and oblates are higher than that of spheres, and as Re increases, the Nuavg of oblates gradually catches up that of prolates and becomes comparable at Re≈200. Moreover, oblates attenuate and intensify the heat transfer at low and high Re at high φ, respectively.

Procedure for in-fly particle temperature detection under combustion conditions

The experimental test rig for evaluating the diameter and mass loss of burning pulverized coal char particles has been extended by providing in-fly particle temperature measurement technique based on two-color pyrometry. Due to the use of two fast cameras it was possible to detect temperature simultaneously with particle tracking in test chamber. The proper resolution of the cameras and focal length of the lenses allow to measure temperature distribution at the surface of individual particles. Procedures for calibration and temperature measurements have been developed and described. Preliminary measurements were made for two types of coal (lignite and hard coal) in two oxygen concentrations (15% and 21%) and gas temperature of 1000∘C.

Modeling of inter- and intra-particle coating uniformity in a Wurster fluidized bed by a coupled CFD-DEM-Monte Carlo approach

A coupled CFD-DEM and Monte Carlo approach was developed to investigate coating properties in a Wurster fluidized bed by considering gas flow, particle motion, droplet deposition, and the drying and solidifying of droplets on particle surfaces. Based on the spherical centroidal Voronoi tessellation (CVT), the Monte Carlo approach can model the deposition and splashing of spray droplets on the surface of individual particles. The capillary force induced by liquid bridges between particles was accounted in the DEM to investigate its influence on the coating and agglomeration behavior. The new model can provide information about the cycle time distribution, residence time distribution, coating coverage, uniformity of porosity (influenced by splashing) and layer thickness distributions on each individual particle (intra-particle) and in the particle population (inter-particle). The simulation results are compared with experimental data on residence time and intra-particle layer thickness distributions. Good agreement is observed between the simulation and the measurements.

Effect of fluoroethylene carbonate as an electrolyte solvent in the LiNi0.5Mn1.5O4/Li4Ti5O12 cell

Fluoroethylene carbonate (FEC) is used as solvent for the antioxidation electrolyte system in the LiNi0.5Mn1.5O4/Li4Ti5O12 cell. We use scanning electron microscopy to analyze the solid electrolyte interphase (SEI) film covered from the surface of individual particles to the top of electrodes. The stable, uniform SEI films formed on individual Li4Ti5O12 particles with FEC solvent are responsible for the significantly improved electrochemical performance. Meanwhile, our results show that severe swelling could be observed and heavier manganese (Mn2+) deposition could be detected on top of the Li4Ti5O12 electrode surface. In this study, we adopt the metathesis reaction to illustrate the relationship between gradual changes in the SEI film and swelling problems during cycling performance. Moreover, the reduction mechanisms of FEC proposed in this study have provided a better understanding of the key issue on electrolyte system that for commercial LiNi0.5Mn1.5O4/Li4Ti5O12 cell.

Using X-ray computed tomography and micro-Raman spectrometry to measure individual particle surface area, volume, and morphology towards investigating atmospheric heterogeneous reactions

Heterogeneous reactions on the aerosol particle surface in the atmosphere play important roles in air pollution, climate change, and global biogeochemical cycles. However, the reported uptake coefficients of heterogeneous reactions usually have large variations and may not be relevant to real atmospheric conditions. One of the major reasons for this is the use of bulk samples in laboratory experiments, while particles in the atmosphere are suspended individually. A number of technologies have been developed recently to study heterogeneous reactions on the surfaces of individual particles. Precise measurements on the reactive surface area, volume, and morphology of individual particles are necessary for calculating the uptake coefficient, quantifying reactants and products, and understanding the reaction mechanism better. In this study, for the first time we used synchrotron radiation X-ray computed tomography (XCT) and micro-Raman spectrometry to measure individual CaCO3 particle morphology, with sizes ranging from 3.5–6.5μm. Particle surface area and volume were calculated using a reconstruction method based on software three-dimensional (3-D) rendering. The XCT was first validated with high-resolution field-emission scanning electron microscopy (FE-SEM) to acquire accurate CaCO3 particle surface area and volume estimates. Our results showed an average difference of only 6.1% in surface area and 3.2% in volume measured either by micro-Raman spectrometry or X-ray tomography. X-ray tomography and FE-SEM can provide more morphological details of individual CaCO3 particles than micro-Raman spectrometry. This study demonstrated that X-ray computed tomography and micro-Raman spectrometry can precisely measure the surface area, volume, and morphology of an individual particle.

Modular Self-Assembly of Protein Cage Lattices for Multistep Catalysis.

The assembly of individual molecules into hierarchical structures is a promising strategy for developing three-dimensional materials with properties arising from interaction between the individual building blocks. Virus capsids are elegant examples of biomolecular nanostructures, which are themselves hierarchically assembled from a limited number of protein subunits. Here, we demonstrate the bio-inspired modular construction of materials with two levels of hierarchy: the formation of catalytically active individual virus-like particles (VLPs) through directed self-assembly of capsid subunits with enzyme encapsulation, and the assembly of these VLP building blocks into three-dimensional arrays. The structure of the assembled arrays was successfully altered from an amorphous aggregate to an ordered structure, with a face-centered cubic lattice, by modifying the exterior surface of the VLP without changing its overall morphology, to modulate interparticle interactions. The assembly behavior and resultant lattice structure was a consequence of interparticle interaction between exterior surfaces of individual particles and thus independent of the enzyme cargos encapsulated within the VLPs. These superlattice materials, composed of two populations of enzyme-packaged VLP modules, retained the coupled catalytic activity in a two-step reaction for isobutanol synthesis. This study demonstrates a significant step toward the bottom-up fabrication of functional superlattice materials using a self-assembly process across multiple length scales and exhibits properties and function that arise from the interaction between individual building blocks.

High-temperature adsorption layers based on fluoridated polyimide and diatomite carrier

A way of preparing separation layers by the pyrolysis of fluorinated polyimide obtained from 2,4,6-trimethyl-m-phenylenediamine (2,4,6-TMmPDA) and 2,2-bis(3′,4′-dicarboxyphenyl)hexafluoropropane (6FDA) applied onto a diatomite carrier is described. Thermogravimetry, elemental analysis, low-temperature nitrogen adsorption, high-resolution electron microscopy, and gas chromatography are used to study changes in the texture and chromatographic characteristics of these layers. It is found that changes in the structure and the effectivity of separation characteristic of the layers depend on the temperature of pyrolysis, which ranges from 250 to 1100°C. It is established that a layer of separation is formed at 250–350°C, and the order of elution of hydrocarbons is similar to their chromatographic behavior on such stationary phases as OV-101. Layers of amorphous carbon formed on the surfaces of individual particles on a diatomite surface at 500–700°C. These layers ensure highly stable and selective separation of permanent gases and hydrocarbons when they are present together.

A new contact liquid dispersion model for discrete particle simulation

In wet granulation and particle coating, it is important to accurately predict the liquid dispersion for process optimisation and quality assurance. In this work, a new contact dispersion model is proposed by taking into account the partial wetting of particle surfaces, which is incorporated into the Discrete Element Method (DEM). In the proposed model, individual particle surfaces are sub-divided and the liquid redistribution between these sub-divided surfaces are tracked with time. The proposed model is applied to simulate a spray drum where liquid is sprayed to initially dry particles, and the liquid dispersion rate is compared with the results obtained from the Shi and McCarthy model (Shi and McCarthy, 2008), which is one of the pioneering models for contact liquid dispersion in DEM. It is found that the Shi and McCarthy model gives faster liquid dispersion when highly viscous liquid is used, whilst the results are largely comparable in the low viscosity case.

Metal hybrid nanoparticles for catalytic organic and photochemical transformations.

In order to understand heterogeneous catalytic reactions, model catalysts such as a single crystalline surface have been widely studied for many decades. However, catalytic systems that actually advance the reactions are three-dimensional and commonly have multiple components including active metal nanoparticles and metal oxide supports. On the other hand, as nanochemistry has rapidly been developed and been applied to various fields, many researchers have begun to discuss the impact of nanochemistry on heterogeneous catalysis. Metal hybrid nanoparticles bearing multiple components are structurally very close to the actual catalysts, and their uniform and controllable morphology is suitable for investigating the relationship between the structure and the catalytic properties in detail. In this Account, we introduce four typical structures of metal hybrid nanoparticles that can be used to conduct catalytic organic and photochemical reactions. Metal@silica (or metal oxide) yolk-shell nanoparticles, in which metal cores exist in internal voids surrounded by thin silica (or metal oxide) shells, exhibited extremely high thermal and chemical stability due to the geometrical protection of the silica layers against the metal cores. The morphology of the metal cores and the pore density of the hollow shells were precisely adjusted to optimize the reaction activity and diffusion rates of the reactants. Metal@metal oxide core-shell nanoparticles and inverted structures, where the cores supported the shells serving an active surface, exhibited high activity with no diffusion barriers for the reactants and products. These nanostructures were used as effective catalysts for various organic and gas-phase reactions, including hydrogen transfer, Suzuki coupling, and steam methane reforming. In contrast to the yolk- and core-shell structures, an asymmetric arrangement of distinct domains generated acentric dumbbells and tipped rods. A large domain of each component added multiple functions, such as magnetism and light absorption, to the catalytic properties. In particular, metal-semiconductor hybrid nanostructures could behave as effective visible photocatalysts for hydrogen evolution and CO oxidation reactions. Resulting from the large surface area and high local concentration of the reactants, a double-shell hollow structure showed reaction activities higher than those of filled nanoparticles. The introduction of plasmonic Au probes into the Pt-CdS double-shell hollow particles facilitated the monitoring of photocatalytic hydrogen generation that occurred on an individual particle surface by single particle measurements. Further development of catalysis research using well-defined metal hybrid nanocatalysts with various in situ spectroscopic tools provides a means of maximizing catalytic performances until they are comparable to or better than those of homogeneous catalysts, and this would have possibly useful implications for industrial applications.

Simulations of liquid-to-solid mass transfer in a fluidized microchannel

Liquid-to-solid mass transfer in a microfluidized bed consisting of monosized, spherical particles in a Newtonian liquid has been studied numerically. The simulations fully resolve the laminar, near-creeping flow of the solid–liquid suspension. In addition, passive scalar concentrations in the liquid at high Schmidt number (Sc up to 104) have been determined. Solids volume fractions are in the range 0.18–0.27. The concentration boundary conditions are such that the scalar can be thought of as being adsorbed on the solid particle surfaces. The simulations quantify the overall adsorption performance of the fluidized bed, and they provide insights in local variations (per particle and over individual particle surfaces) of mass transfer rates.

Plasmon-Enhanced Enzyme-Linked Immunosorbent Assay on Large Arrays of Individual Particles Made by Electron Beam Lithography

Ultrasensitive biosensing is one of the main driving forces behind the dynamic research field of plasmonics. We have previously demonstrated that the sensitivity of single nanoparticle plasmon spectroscopy can be greatly enhanced by enzymatic amplification of the refractive index footprint of individual protein molecules, so-called plasmon-enhanced enzyme-linked immunosorbent assay (ELISA). The technique, which is based on generation of an optically dense precipitate catalyzed by horseradish peroxidase at the metal surface, allowed for colorimetric analysis of ultralow molecular surface coverages with a limit of detection approaching the single molecule limit. However, the plasmonic response induced by a single enzyme can be expected to vary for a number of reasons, including inhomogeneous broadening of the sensing properties of individual particles, variation in electric field enhancement over the surface of a single particle and variation in size and morphology of the enzymatic precipitate. In this report, we discuss how such inhomogeneities affect the possibility to quantify the number of molecules bound to a single nanoparticle. The discussion is based on simulations and measurements of large arrays of well-separated gold nanoparticles fabricated by electron beam lithography (EBL). The new data confirms the intrinsic single-molecule sensitivity of the technique but we were not able to clearly resolve the exact number of adsorbed molecules per single particle. The results indicate that the main sources of uncertainty come from variations in sensitivity across the surface of individual particles and between different particles. There is also a considerable uncertainty in the actual precipitate morphology produced by individual enzyme molecules. Possible routes toward further improvements of the methodology are discussed.

Structure of Mg–C nanocomposites produced by mechano-chemical synthesis

The carbon distribution in the Mg–C composites produced by ball milling of elemental magnesium with amorphous carbon and graphite powder was studied by X-ray diffractometry (XRD), transmission electron microscopy (TEM), Auger electron spectrometry (AES) and X-ray photoelectron spectrometry (XPS). Specific surface area of the composites was characterized by BET-method. It was found that a thin carbon coating layer on the surface of individual particles is formed. This carbon layer prevents particles agglomeration and promotes the magnesium powdering. A possible structure model of the magnesium–carbon composite has been proposed.

Spontaneous ignition of ultra-fine magnesium powder without an original oxide coat at room temperature in O 2/N 2 mixture streams

To examine the pyrophoric characteristics of Mg powder, we generated ultra-fine Mg particles (average particle diameter: about 0.3 μm) without an original oxide coat in an Ar stream. The ignition of the powder was measured by using the impinging O 2/N 2 mixture streams over a wide range of the experimental parameters: pressure, oxygen concentration and velocity of the streams. The Mg powder was found to ignite even at room temperature. The spontaneous ignition temperatures in the range of 278 ∼ 324 K were insensitive to all the experimental parameters. The ignition delay time had a tendency to decrease with increasing experimental parameters. The ignition process of the Mg powder was found to be controlled by the surface reaction rate without an oxide coat. We proposed a new ignition hypothesis considering a critical oxide thickness on the Mg powder particles at the transition temperature from protective to non-protective nature: that is, the ignition of the Mg powder occurs when the powder temperature rises above the transition temperature before surface reactions form a protective oxide coat with the critical thickness on the individual particle surfaces. According to this hypothesis, an ignition model of Mg powder cluster was developed, and the relation between the spontaneous critical ignition temperature and the ultra-fine powder size, depending on the critical thickness of the protective oxide coat, was clarified. The critical oxide thickness was estimated.

Computing Particle Surface Areas and Contact Areas from Three‐Dimensional Tomography Data of Particulate Materials

AbstractMicrotomography is an emerging technique for particle and particulate‐materials characterization. To use this technology effectively, robust and accurate computational algorithms are needed to compute relevant particle properties, including particle surface area and particle‐particle contact area. However, the most accurate algorithms that have been developed for computing the exposed (void/solid) surface area in a microtomography image cannot be used directly for computing surface areas or particle‐particle contact areas for individual particles in a dense packing. This paper presents an algorithm for extracting particle contact areas from a digitized, segmented image of a packed granular material, which in turn can be used to find individual particle surface areas (even if the complete surfaces are not exposed because of contacts in the packing). Results show that small errors in the binary surface‐area computations are magnified in the course of determining particle contact areas; the total error in the computation depends mainly on the size of the contact area in voxel units.

Characterization of individual atmospheric aerosol particles with SIMS and laser-SNMS

The surface chemistry of atmospheric aerosol particles is important in determining how these particles will effect human health, visibility, climate and precipitation chemistry. In previous work, it has been shown that ToF-SIMS can provide significant valuable information on both organic and inorganic constituents of the aerosol. It has been found, however, that ToF-SIMS with a Ga + primary ion beam offers very low sensitivity to poly-aromatic hydrocarbons (PAHs) and heavy metals, two important classes of pollutants. In this work the utility of laser-SNMS for detection of these pollutants has been explored. Two laser systems, a 193 nm excimer laser and a 157 nm excimer laser have been utilized. Each approach has advantages. ToF-SIMS has the highest sensitivity to alkali metals and aliphatic hydrocarbons. The 193 nm laser provides very high sensitivity to lead and other metals. The 157 nm laser greatly enhances sensitivity to PAHs which has enabled detection of PAHs on the surface of individual particles.

Application of a cryo-stage in the TOF-SIMS analysis of atmospheric aerosol surfaces

The surface sensitivity and minimal fragmentation available with time-of-flight secondary ion mass spectroscopy (TOF-SIMS) makes it a powerful tool for the examination of the organic and inorganic species on individual particle surfaces. One concern with the technique is the potential loss of volatile and semi-volatile organic compounds in the high vacuum environment. Cryo-cooling in the intro chamber enables us to retain semi-volatile compounds including PAHs and alkanes on surfaces for over an hour in the analytical chamber. Samples collected using an eight-stage Graseby-Anderson cascade impactor included aerosols from winter snowmobile emissions in Yellowstone National Park and urban aerosol from the Salt Lake Valley. Comparison of spectra obtained at ambient temperature with those obtained under cryogenic conditions show a clear loss of both aromatic and aliphatic organic species at ambient temperature.