Liquid Acetone Research Articles

Thermally Powered Soft Gripper Covered with Silver‐Coated Nylon Fabric Heater Reinforced with Stainless Steel Yarn

Soft grippers, generating movement immediately, are generally based on flexible materials actuated by air pressure and comprised of bulky parts, including valves, compressors/pumps, motors, and tubes. In this work, a compact soft gripper with the ability to actuate with a low boiling point liquid (acetone) is presented. SolidWorks 2021 software and 3D printing technology are used to design and manufacture the gripper molds, respectively. The constitutive material of the soft gripper body is highly flexible Ecoflex. A silver‐coated nylon fabric (SCNF) heater reinforced with stainless steel yarn (SSY) covering the external surface of the gripper is designed and manufactured using Autocad 2021 and a laser cutting machine, respectively. The idea is inspired by floating the gripper in warm water to provide smooth heat over a large surface area. The available commercial software Abaqus2021 is used to simulate the mechanical deformation of the gripper, and its results are verified with experimental results. The parameter's effect including the voltage and low boiling liquid volume on achievable force and actuating time are investigated. The relation between the electrical, thermal, and mechanical properties of the presented gripper is discussed in detail.

Photochemistry of Photoinduced-Reaction Generated Bubbles.

UV light can create and grow bubbles (herein referred to as PIRGBs for photoinduced-reaction generated bubbles) at liquid/solid interfaces through photoinduced reactions that produce gases. Unlike the simple experience of blowing water bubbles through a straw, in which the bubbles quickly move away from their nucleation sites, not only can a deep UV laser beam create PIRGBs in liquid acetone, but also can hold and grow them. Free bubbles could be attracted to the excitation region from millimeters away, indicating that the reactions cause radial inward flow on the liquid surface. The radial flow can be due to imbalanced surface tensions at the interfaces. Raman measurements reveal that the gases in the PIRGBs include C2H6, CO, and H2, and in liquid acetone, sp2-carbon species are detected upon the UV excitation. Time series Raman measurement discloses a photocarbonization process in which small acyclic carbon species gradually form small clusters with carbon rings and eventually produce a large piece of amorphous carbon at the top of a PIRGB in pure liquid acetone. The photocarbonization may open new avenues for development of carbonaceous materials. Using PIRGB, miniature or microscale gas production reactors can be developed for producing gases.

Direct Numerical Simulation of Vortex Breakdown in Evaporating Dilute Sprays

AbstractThe effects of different vortex breakdown states on the evaporation process characterizing air-acetone vapor swirling jets laden with liquid acetone droplets in the dilute regime are discussed based on results provided by direct numerical simulations. Adopting the point-droplet approximation, the carrier phase is solved using an Eulerian framework, whereas a Lagrangian tracking of the dispersed phase is used. Three test cases are investigated: one with fully-turbulent pipe inflow conditions and two with a laminar Maxworthy velocity profile at different swirl rates. Consequently, turbulent, bubble-type, and regular conical vortex breakdown states are established. Following phenomenological and statistical analyses of both phases, a significant enhancement of the overall droplet evaporation process due to the onset of the conical vortex breakdown is observed due to the strongest centrifugal forces driving the entire liquid drops towards the low-saturation mixing layer of the jet. The effects of droplet inertia on evaporation are isolated through an additional set of simulations where liquid droplets are treated as Lagrangian tracers. While it is found that inertial effects contribute to enhanced vaporization near the mixing layer under bubble vortex breakdown conditions, droplet inertia plays a secondary role under both turbulent and conical vortex breakdown due to intense turbulent mixing and high centrifugal forces, respectively.

Improved data analysis for molecular dynamics in liquid CCl4

Previously reported inelastic x-ray scattering spectra of a typical van der Waals molecular liquid CCl4 were reanalyzed using a generalized Langevin formalism with a memory function including a thermal and two viscoelastic relaxation processes and simple sparse modeling. The obtained excitations of longitudinal acoustic phonons show a largely positive deviation from the hydrodynamic value by about 57%, much larger than about 37% by the previously reported damped harmonic oscillator result. Such large values of fast sounds in molecular liquids larger than 15-20% of typical liquid metals are interpreted as extra energy losses for terahertz phonons by molecules' vibrational and rotational motions. The rates of the fast and slow viscoelastic relaxations in the memory function at low Q indicate large values, about 0.5 and 2 ps, which correspond to the vibrational and rotational motions of CCl4 molecules, respectively. These values are larger than those of the typical polar molecular liquid acetone, which may reflect the heavier atomic mass of CCl4. The Q dependences of the viscoelastic relaxation rates are discussed in terms of the lifetime and propagating length of the terahertz phonon oscillations. The microscopic kinematic longitudinal viscosity was obtained from the viscoelastic relaxation magnitudes and times, rapidly decreasing with Q from a macroscopic value at Q→0.

Surface Tension of Liquids (Water, Chloroform and Acetone) by Capillary Rise Method

Surface tension is a crucial property of liquids that depends on the liquid's composition. This study aims to compare the surface tension of water, chloroform, and acetone using the capillary rise method. It involves using a capillary tube with a known radius, dipping it vertically into a liquid, and measuring the height to which the liquid rises in the tube. The surface tension of the liquid can then be measured experimentally. This relates to height of the liquid in the tube, the radius of the tube, and the surface tension of the liquid. The height of the liquid in the tube is dependent on the radius of the tube, with a smaller radius resulting in a greater height. The surface tension of the liquid is inversely related to the radius of the capillary tube.

How Pulse Width Affects Laser Ablation of Organic Liquids.

Laser synthesis in liquids is often carried out in organic solvents to prevent oxidation of metals during nanoparticle generation and to produce tailored carbon-based nanomaterials. This work investigates laser ablation of neat organic liquids acetone, ethanol, n-hexane, and toluene with pulse widths ranging from 30 fs to 4 ps through measurements of reaction kinetics and characterization of the ablation products with optical spectroscopy and mass spectrometry. Increasing the pulse width from 30 fs to 4 ps impacts both the reaction kinetics and product distributions, suppressing the formation of solvent molecule dimers and oxidized molecules while enhancing the yields of gaseous molecules, sp-hybridized carbons, and fluorescent carbon dots. The observed trends are explained in the context of established ionization mechanisms and cavitation bubble dynamical processes that occur during ultrashort pulsed laser ablation of liquid media. The results of this work have important implications both for controlling the formation of carbon shells around metal nanoparticles during the ablation of solid targets in liquid and producing carbon nanomaterials directly from the ablation of organic liquids without a solid target.

Anomalous diffusion, gigahertz, and terahertz spectroscopy of aliphatic ketones.

The experimental results of the complex dielectric permittivity of aliphatic ketones in dilute solutions of inert solvent cyclohexane in the gigahertz (GHz) and terahertz (THz) frequencies of the electromagnetic spectrum are examined in terms of the theory of inertial anomalous diffusion of polar molecules, considered as an assembly of molecules with interacting dipolar groups, in polar liquids. The theory is based on the generalization of the Debye rotational diffusion model of dielectric relaxation of polar molecules. The model comprises two interacting dipolar groups-one lighter and the other heavier; each has a finite moment of inertia and each experiences a finite friction with an extensive range of damping or drag coefficient and the dipole moment ratio of the two groups. The lighter group refers to the reference molecule, whereas the heavier group simulates the neighboring molecules, and the two groups interact with each other via the dipole-dipole interaction potential. The resulting approximate expression contains terms in both the Rocard form and the Сole-Сole form. The experimental data on aliphatic ketones are shown to fit extremely well with the theory, and parameters of the fit offer physical significance. An agreement of the plot of the experimental data on dielectric loss versus frequency to the formulas derived from the model offers a mathematical basis of the semiempirical equations used in the literature to fit the experimental data. Experimental results of the dielectric loss of neat polar liquid acetone in GHz and THz, as an example, are shown to fit the theory; however, the interaction potential parameter compared to its dilute solution counterpart is significantly increased, reflecting the increase in the dipole-dipole interaction energy.

Effect of Silicate Additive on Structural and Electrical Properties of Germanium Nanowires Formed by Electrochemical Reduction from Aqueous Solutions.

Layers of germanium (Ge) nanowires (NWs) on titanium foils were grown by metal-assisted electrochemical reduction of germanium oxide in aqueous electrolytes based on germanium oxide without and with addition of sodium silicate. Structural properties and composition of Ge NWs were studied by means of the scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy. When sodium silicate was added to the electrolyte, Ge NWs consisted of 1–2 at.% of silicon (Si) and exhibited smaller mean diameter and improved crystallinity. Additionally, samples of Ge NW films were prepared by ultrasonic removal of Ge NWs from titanium foils followed with redeposition on corundum substrates with platinum electrodes. The electrical conductivity of Ge NW films was studied at different temperatures from 25 to 300 °C and an effect of the silicon impurity on the thermally activated electrical conductivity was revealed. Furthermore, the electrical conductivity of Ge NW films on corundum substrates exhibited a strong sensor response on the presence of saturated vapors of different liquids (water, acetone, ethanol, and isopropanol) in air and the response was dependent on the presence of Si impurities in the nanowires. The results obtained indicate the possibility of controlling the structure and electrical properties of Ge NWs by introducing silicate additives during their formation, which is of interest for applications in printed electronics and molecular sensorics.

Considerations for the Maximum Heat Load and Its Influence on Temperature Variation of the Evaporator in Flat MHPs in Transient Regimes.

The present paper describes a series of considerations for the occurrence of capillary boundaries in flat micro heat pipes (flat MHPs) and the conditions required for their stable operation in relation to the working circumstances and to the type of liquids inside the pipes. Particularities of heat transfer in a flat MHP are analyzed for situations of either excessive or deficient working liquid. Depending on the physical properties of the working liquids (acetone, methanol and distilled water), the maximum rate of heat flow that can be applied to a flat MHP is determined analytically. The calculus is made with the assumption that constant vaporization of the liquid is ensured in the flat MHP’s evaporator, with no overheating. The considered analytical models allow for the evaluation of the liquid film thickness and the mass flow corresponding to the vaporization region. The temperature difference between the inner and outer walls of a flat MHP is found in the case of a transient regime and a variable thermal flow is applied in the evaporation region. The interior of flat MHPs was modeled in MATLAB using an FTCS (Forward-Time Central-Space) method, which is a finite difference method used for numerically solving the heat equation.

Synthesis of Titanium Nitride Nanoparticles by Pulsed Laser Ablation in Different Aqueous and Organic Solutions.

Owing to a strong photothermal response in the near-IR spectral range and very low toxicity, titanium nitride (TiN) nanoparticles (NPs) synthesized by pulsed laser ablation in liquids (PLAL) present a novel appealing object for photo-induced therapy of cancer, but the properties of these NPs still require detailed investigation. Here, we have elaborated methods of femtosecond laser ablation from the TiN target in a variety of liquid solutions, including acetonitrile, dimethylformamide, acetone, water, and H2O2, to synthesize TiN NPs and clarify the effect of liquid type on the composition and properties of the formed NPs. The ablation in all solvents led to the formation of spherical NPs with a mean size depending on the liquid type, while the composition of the NPs ranged from partly oxidized TiN to almost pure TiO2, which conditioned variations of plasmonic peak in the region of relative tissue transparency (670–700 nm). The degree of NP oxidation depended on the solvent, with much stronger oxidation for NPs prepared in aqueous solutions (especially in H2O2), while the ablation in organic solvents resulted in a partial formation of titanium carbides as by-products. The obtained results contribute to better understanding of the processes in reactive PLAL and can be used to design TiN NPs with desired properties for biomedical applications.

Structural studies of 1H-containing liquids by polarized neutrons: Chemical environment and wavelength dependence of the incoherent background

Following a demonstration of how neutron diffraction with polarization analysis may be applied for the accurate determination of the coherent static structure factor of disordered materials containing substantial amounts of proton nuclei (Temleitner et al., Phys. Rev. B 92, 014201, 2015), we now focus on the incoherent scattering. Incoherent contributions are responsible for the great difficulties while processing standard (non-polarized) neutron diffraction data from hydrogenous materials, hence the importance of the issue. Here we report incoherent scattering intensities for liquid acetone, cyclohexane, methanol and water, as function of the 1H/H ratio. The incoherent intensities are determined directly by polarized neutron diffraction. This way, possible variations of the incoherent background due to the changing chemical environment may be monitored. In addition, for some of the water samples, incoherent intensities as a function of the wavelength of the incident neutron beam (at 0.4, 0.5 and 0.8 Å) have also been measured. It is found that in each case, the incoherent intensity can be described by a single Gaussian function, within statistical errors. The (full) width (at half maximum) of the Gaussians clearly depends on the applied wavelength. On the other hand, the different bonding environments of hydrogen atoms do not seem to affect the width of the Gaussian.

Mixing characteristics of liquid jet injected behind a curved pylon in supersonic flow

Mixing of liquid jet in Mach 1.71 crossflow using a curved pylon configuration has been studied experimentally. The liquid acetone jet was injected at 60° against the free stream airflow behind the pylon. High-speed Schlieren and Mie scattering experiments were performed to evaluate the mixing characteristics of liquid jet injected behind the curved pylon. POD and SPOD analyses were employed on the high-speed Schlieren images to observe the coherent structures, their energy levels, and frequencies at which these structures occur. Results showed improvements in penetration height and the lateral spread of liquid jet for the curved pylon configuration. The penetration height of the liquid jet was 7.79% more for the curved pylon case as compared with the standard pylon case for the same momentum flux ratio. Further increase in the momentum flux ratio increased the penetration height to 15.53% more as compared with the standard pylon case. The spread area of the liquid jet was 17.42% more at x/dj=25 and 25.97% more at x/dj=40 for the curved pylon case than the standard pylon case for the same momentum flux ratio. The presence of counter-rotating vortices at the top of the liquid plume and in the near-wall region caused a higher spread area in curved pylon cases as compared with standard pylon cases.

Intermolecular interaction network in liquid acetone

Molecular dynamics simulations, employing the transferable potentials for phase equilibria-united atom force field, have been performed to explore the structural features of liquid acetone. Topological and dynamical network analyses have been performed on the intermolecular interaction (IMI) networks, which are constructed based on a set of pair energy cutoffs. Topological analysis revealed that the acetone pairs interacting stronger than −10 kJ/mol exist as isolated pairs in a sense that the members of the pair do not interact with other molecules with an energy smaller than −10 kJ/mol. As such, those strongly interacting pairs do not constitute a three-dimensional extended network. As the pair interaction energy cutoff becomes larger than −10 kJ/mol, the IMI network starts to become a three-dimensional extended network and its connectivity increases gradually. Dynamical analysis revealed that the decay function for intermolecular interaction lifetimes is characterized by a nonexponential decay for all the IMI networks such that it decays faster at short-times in comparison to the longer-times. Yet, the duration of the intermolecular interactions can go beyond 1.0 ps for the pairs with the interaction energies larger than −6 kJ/mol. Furthermore, the orientational correlations in the liquid acetone have been examined for a more detailed picture of its structure. It is clearly shown that as the distance between the carbonyl carbons of the two acetones gets smaller, (i) they tend to adopt an anti-parallel dipole orientation, (ii) the planes of the acetones tend to adopt a parallel orientation, and, (iii) such acetone pairs particularly interact more strongly. In the light of these findings, two dimeric structures, stack-type and planar-type, are highlighted. Using density functional theory (DFT) at the mPW2PLYP/def2-TZVP level, the interaction energy in the gas-phase is computed to be −19.85 kJ/mol for the stack-type dimer, which is more stable than the planar-type dimer by 7.7 kJ/mol. Both the gas-phase DFT interaction energy and the computed acetone dipole moment, 2.97 D, are in great agreement with the corresponding experimental data. Furthermore, in accordance with the gas-phase results, the stack-type dimers are found to be more stable than the planar-type dimers also in the liquid-phase as revealed from both the liquid-phase DFT interaction energies and the MD based mean interaction energies. Finally, trimeric structure search in the simulated liquid acetone revealed that of all trimers, 94% belongs to the chain-like trimers, while the remaining 6% belongs to the cyclic trimers.

Improving the mechanical properties and coefficient of thermal expansion of molybdenum-reinforced copper using powder metallurgy

This paper presents an experimental study of Cu-Mo alloys prepared by powder metallurgy (PM) method. Also, improving the dispersion and wettability of Mo in the Cu matrix was aimed. Mo particles were added by 0.24, 0.48, 0.73 and 0.97% volume fraction to Cu powder. The mixture was mechanically milled by planetary ball mill at a rotational speed of 140 rpm for 24 h under hydrogen atmosphere, with milling ball size of ∼25 times the size of the metal powders. Liquid acetone was utilized as a process control agent (PCA). Paraffin wax (0.5 wt%) was used to decrease the friction with die during the compaction process. The mixture of the blended powder was compacted at ambient temperature under three different pressures (400, 600 and 800 MPa) and then sintered in a vacuum furnace at 1000 °C for 1 h by a heating rate of 5 °C min−1. The microstructure examination showed a homogeneous dispersion of Mo particles within the Cu matrix with no evidence of new phases formation during the sintering process. Also, the relative density of samples has been increased by increasing both of Mo content and the compaction pressure. The results revealed that the compaction pressure of 600 MPa was the most suitable pressure as it gave the highest densification. Cu—0.97% volume fraction Mo alloy samples exhibited finer Mo particles with a homogenous distribution in the Cu matrix and well bonding with the Cu particles. The microhardness was increased gradually by increasing Mo wt%, while the compressive strength was decreased by increasing the Mo contents. Both the electrical and thermal conductivities were decreased gradually by the addition of Mo. While the coefficient of thermal expansion (CTE) was decreased by Mo addition.

Application of the principal components analysis technique to optical fiber sensors for acetone detection

Generally, the data analysis of sensors based on spectral measurements, for instance, fiber Bragg gratings (FBG), long period fiber gratings (LPFG) is performed observing the shift or attenuation of a single wavelength. However, sometimes such spectrum variations are not evident or clearly perceptible; therefore, it becomes necessary to use other analysis techniques. One of them is principal components analysis (PCA) which allows to explore the behavior of the complete transmission spectrum pattern. In this work, we show the application of PCA to the response of fiber optical sensors for acetone detection. Two kinds of acetone sensors based upon single long period fiber gratings (LPFG) and Mach-Zehnder fiber interferometers (MZI), formed with a pair of cascaded LPFGs, coated with polydimethylsiloxane (PDMS) were developed. The sensor response was measured inside a Teflon chamber injecting a liquid acetone sample. The transmission spectrum variations at the devices output were measured with an optical spectrum analyzer, stored in a computer and analyzed by PCA. A comparison between the performance of both kinds of sensors was carried out and it was found that the sensitivity was increased up to 13 times (from 0.7 × 10−4 ppm−1 to 9.4 × 10−4 ppm−1) for the MZI sensors compared with that of single LPFG ones, which means, at best, a limit of detection (LOD) of 170 ppm.

Subnanoliter Sensing of Dielectric Properties of Liquid-in-Flow at 190 GHz

Dielectric properties (permittivity and loss tangent) of various liquids (water, methanol, propanol, acetone, and isopropanol) are determined by analyzing the frequency detuning effects of different millimeter-wave resonators exposed by the liquid-under-test. Alumina ceramic spherical dielectric resonators, fed from a thin-film circuit, form a resonator fixture operating at 190 GHz. Subnanoliter amount of liquid, carried in a glass tube, is exposed to the resonator. Analysis of the setup by means of electromagnetic field simulations reveals the liquid’s dielectric properties. Extracted data match well with properties obtained from Debye models. Measurement sensitivity is discussed with respect to frequency shift, sensed volume, and dielectric contrast. Obtained sensitivity figure-of-merit outperforms alternative techniques at such high frequency.

Surface modification of sintered magnesium oxide (MgO) with chromium oxide (Cr2O3) by pulsed laser irradiation in air and liquids

Surface modification of ceramic materials by laser irradiation is widely used as a non-contact, fast and thermally activated process to generate micro and nanostructures. The effects of liquids while surface modification by laser irradiation of ceramic materials under liquid environment are least explored so far. This study reports the effects of pulsed laser irradiation in air and liquids on the microstructure and morphologies of ceramic materials. Chromium oxide (Cr2O3) was mixed in different concentrations (3, 5 and 7% in weight) into magnesium oxide (MgO) matrix and was sintered at 1650 °C. The structure and morphology of the sintered ceramic pellets were characterized using X-ray diffraction and scanning electron microscopy. Presence of the spinel magnesium chromium oxide (MgCr2O4) was identified in these samples. For surface modification of these samples, laser irradiation is carried out in air and liquids (methanol, isopropyl alcohol and acetone) using 2 ns pulsed lasers (532 nm) of different pulse repetition rates and energies. The microstructure and morphologies of the samples after irradiation was analyzed and their crystalline structure and composition were maintained after laser irradiation. It was observed that the surface morphologies of the ceramic pellets were modified by laser irradiation as a combined effect of the medium (air/liquids), energy fluence and the concentration of the Cr2O3 in MgO. Our results show that pulsed laser irradiation especially in liquids is an effective technique for modifying surface morphology of ceramic materials.

Collective dynamics of liquid acetone investigated by inelastic X-ray scattering

The dynamic structure factors S(Q,ω) of liquid acetone were measured in a wide Q range 1.9–41.2 nm−1 with a high-resolution inelastic X-ray scattering (IXS) spectrometer installed at BL35XU of the SPring-8. Highly damped collective excitations of the longitudinal acoustic (LA) phonons are observed. The IXS spectra were analyzed by using a generalized Langevin formalism with the help of a sparse modeling to deduce reasonable Q dependences of the fitting parameters. The dispersion relation of the LA phonon excitations shows a highly positive deviation by about 65% from the adiabatic velocity of sound, which is larger than that in non-polar liquids such as CCl4 and benzene with van der Waals interactions, due probably that the acetone is a polar liquid. Microscopic dynamic parameters, such as viscoelastic relaxation rates and viscosity, are discussed by comparing with existing macroscopic dynamic properties. The fast and slow viscoelastic relaxations correspond to the vibration dynamics and reorientation correlations, respectively.

Revealing Molecular Mechanisms in Hierarchical Nanoporous Carbon via Nuclear Magnetic Resonance

Author(s): Mao, H; Tang, J; Xu, J; Peng, Y; Chen, J; Wu, B; Jiang, Y; Hou, K; Chen, S; Wang, J; Lee, HR; Halat, DM; Zhang, B; Chen, W; Plantz, AZ; Lu, Z; Cui, Y; Reimer, JA | Abstract: Hierarchical nanoporous carbons combining pore sizes of different length scales are highly important for separation processes. However, critical questions remain regarding the hierarchical structure regulation and the molecular mechanisms of gaseous adsorbate uptake and interactions within the hierarchical nanoporous carbons. These materials present characterization challenges in that there are no experimental techniques that can elucidate the molecular mechanisms of the organic compounds and CO within the materials. We deployed multidimensional solid-state nuclear magnetic resonance (NMR) to generate maps of guest-framework interactions as a function of adsorbate concentrations and adsorption times. The NMR spectra provide insight toward the design of effective hierarchical pore structures. Our materials show a high volatile organic compounds/CO physisorption capacity, which reveals promising application to carbon-capture strategies to mitigate global warming. 2 2

A method for measuring droplet evaporation in a shock-driven multiphase instability

Experimental measurements of bulk droplet evaporation within a shock-driven multiphase instability, or SDMI, were studied using advanced imaging diagnostics. Specifically, droplet evaporation was quantified by determining the rate of acetone vapor produced from liquid acetone droplets. The extent of the acetone vapor produced was measured using quantitative planar laser-induced fluorescence (Q-PLIF). In addition to vapor concentration, Q-PLIF also accounts for the effects of pressure and temperature on the fluoresced acetone. Concurrently performed with Q-PLIF were particle image velocimetry (PIV) measurements as the means to gather data on the acetone droplet’s velocities as well as the particle fields morphology throughout its development. By using these two diagnostic techniques, two successive data points of the acetone droplets evaporation rate throughout the development of the SDMI were obtained. Although these first two data sets were not adequate to fully prescribe an accurate evaporation rate model, they were a sufficient corrigendum to the commonly-utilized D-squared evaporation law. Overall, the previous techniques have been demonstrated that acetone droplet evaporation can be measured quantitatively, enabling prediction of evaporation enhancement due to the strong hydrodynamic mixing within the SDMI.