Large Volumes Of Liquid Research Articles

Large impact features on Ganymede and Callisto as revealed by geological mapping and morphometry

The icy Galilean satellites are host to a broad range of impact feature morphologies. Hypotheses seeking to explain the diversity of these impact features consider the effects of impact melt, the physical state of the subsurface at the time of impact, and the impactor characteristics. As part of a larger effort to assess the role of these factors in the formation and evolution of these impact features, we have performed topographic and geological mapping of 19 large impact features on Ganymede and Callisto. These are divided into two main morphological groups: craters (subdivided into pit, dome, and anomalous dome craters), and penepalimpsests/palimpsests. The transitions from pit, dome, to anomalous dome craters appear to be size-dependent up to diameters of ∼170 km. The morphologies of pit and dome craters appear to be independent of their age or geologic context. The impacts that formed them only affected a cold, rigid ice layer, with the development of pits and raised annuli on their floors possibly stemming from the evolution of a pocket of impact melt. The subdued rims and floors of anomalous dome craters indicate the increasing effect of a weak, warm ice layer on impact feature morphology with increasing size, but their prominent annuli and pits indicate that mobilization of impact melt is also a factor. The very low topographic relief of older penepalimpsests and palimpsests indicates that their impacts penetrated the ice shell to mobilize very large volumes of pre-existing liquid from a subsurface layer, with little contribution to the final feature morphology from impact melt. Penepalimpsests are distinguished from palimpsests by the higher frequency of concentric ridges within their interiors, indicating a generally more robust state of the subsurface that could better support the rotation and uplift of solid material during impact, even if a crater-like depression could not be supported. A few impact features seem to be transitional between anomalous dome craters and penepalimpsests, and the overlap of anomalous dome craters, penepalimpsests, and palimpsests in terms of diameter as well as age indicates that impactor size and subsurface properties over time are major factors in determining which of these morphologies emerges.

Simulation of resonant liquid sloshing in a tank with vertical baffles

The material presents the results of numerical modeling of internal fluid flows geometry in tanks that are subject to fluctuations due to external force influences. Similar applied problems occur when transporting large volumes of liquid, for example, in tanker ships. Given the rather significant moving masses within the reservoirs (tanks), as a rule, there are shock pressures on the walls and internal structures of the guiding devices, which can cause their deformation and even destruction, which leads to serious emergency situations.Numerous studies devoted to the determination of the force effects of liquid flows on the walls of tanks came to the conclusion that the presented phenomena are of a strongly nonlinear nature, depend not only on the amount of liquid and the directions of its movement within the tank, but also on the formation of velocity and pressure fields over time. The specified parameters are decisive in predicting possible resonance phenomena in tanks, which in turn can become the main factor in the design of means of damping or control of inertial fluid flows.The proposed work is devoted to the mathematical modeling of the mentioned phenomena in tanks, as well as the analysis of the force effect of internal inertial flows, which cause the occurrence of shock pressures on internal structures. On the basis of the indicated research results, it is possible to propose rational from the point of view of damping the design of guide devices in the form of flat rigid baffles.

Internal radiation effect on semiconductor β-Ga2O3 crystals grown by the VB Method and anisotropic thermal stress

Gallium oxide crystals are semitransparent semiconductors with good optical and electrical properties, which allow their use for several technological applications. During the growth process of β-Ga2O3 crystals, internal radiation plays a crucial role that affects the growth process and then the crystal quality. In this work, the effect of the melt and the crystal transparency on the vertical Bridgman growth of β-Ga2O3 oxide is thoroughly studied. Using a global 2D/3D finite element model, temperature, melt flow, melt-crystal interface, and three-dimensional anisotropic thermal stress are computed at different growth stages. At each stage, four cases are considered, namely, opaque melt and crystal, semi-transparent melt and opaque crystal, semitransparent crystal and opaque melt, and finally semitransparent melt and crystal. The role of internal radiation in each case at different growth stages is then highlighted separately and then coupled together. It was found that the melt-crystal interface is shifted from a convex shape at the early stage to a nearly plane and then to a concave shape at the last stage. The melt flow is then changed from two rolls pattern at the beginning to a single-roll structure at the last stage. Thermal stress of the as-grown ingot is decreased during the growth due to the decrease of temperature non-linearities. Internal radiation inside the crystal acts to increase the melt-crystal interface convexity at the early and middle stages of the growth process and leads to a decrease in its concavity at the final stage. However, the melt transparency leads to the opposite effects, i.e., it decreases the interface convexity at the early stage and increases the interface concavity at the final stage. As a result, for semitransparent crystal and melt, the interface is between the two previous cases. The calculated thermal stresses are found to be more affected by the transparency of the crystal than the melt as the absorption coefficient of β-Ga2O3 crystal is smaller than that of the melt. At all stages, the thermal stresses are found to be larger for the opaque case due to the increase of temperature non-linearities in the crystal. Large values are found at the bottom and the lower part of the periphery. Furthermore, internal radiation inside the melt plays a major role during the early growth stage due to the large liquid volume. It reduces the melt flow intensity close to the free surface where the shear stress is combined with the buoyant force and leads to the flattening of the interface decreasing then the radial temperature gradients, which leads to small attenuation of the thermal stress. At the final stage, the transparency of the melt plays the opposite role due to the increase of the interface concavity which leads to an increase in both of the temperature gradients and the thermal stress inside the crystal. Due to the crystal anisotropy, and especially to the large thermal expansion coefficient in the [010] direction, the 3D thermal stress values are found to be larger in this direction, especially in the bottom part of the ingot. Comparisons with available experimental and numerical works are provided in this paper.

Numerical Modelling of Cylindrical Fluid Filled Tank

The demand for drinking and service water storage is rising with changing climate conditions and increasing life expectancy. The tanks are commonly used to store large volumes of liquids and materials in various fields of the economy. This paper presents the model of the numerical simulation for the steel tank filled with fluid, using the finite element method. The results of the tank filled with water are presented, by the results: the pressure of the fluid the effective stress, and the maximum deformation of the tank solid domain. The correctness of the pressure values was verified by the simple calculation of the fluid pressure. Finally, the paper documents the results for various fluid fillings with a considered range of fluid densities. The influence of the fluid filling height on the behavior of the solid domain of the fluid filling container loaded by the static loading as well as the effect of the width of the tank on the behavior of the solid domain of the fluid filling container.

Design of liquid level detection circuit based on sampling probe structure capacitance.

Liquid level detection system is an essential core functional component of automatic clinical medical testing instrument. The conventional liquid level detection method has low detection accuracy and sensitivity, and may have the problem of false detection, which may lead to the inaccurate test results. This paper presents a high sensitivity liquid level detection system based on the principle of variable capacitance. When the sampling probe contacts the liquid level, the probe capacitance will change. The liquid level detection circuit board judges whether the probe contacts the liquid level by sensing the change of probe capacitance. When judging the liquid level signal, the combination of slope detection and amplitude detection is used. The liquid level detection circuit board takes the phase-locked loop(PLL) circuit as the center to detect the change of the capacitance. The reference signal of the PLL is set as a square wave of 375kHz. The double tube probe is used as a part of the tuning capacitor of the voltage controlled oscillator to control the frequency of the output signal, which can realize the rapid phase locking. The experimental results show that the system has accurate detection results, high sensitivity, stable and reliable operation, good dynamic response performance in the case of large and small liquid volume. Compared with other liquid level detection methods based on machine vision, ultrasonic, optics and so on, the proposed liquid level detection system has simpler structure and lower cost, it can avoid the problems of collision, carryover contamination and empty suction by controlling the depth of sampling needle inserted into liquid.

Fire-Extinguishing Dibromomethane Mixtures with Fluorinated Alkanes for Fire and Explosion Protection of Oil and Gas Industry Facilities

The high fire hazard level is specific to the oil and gas industry due to the circulation of large volumes of flammable gases and liquids. To ensure fire protection at the oil and gas industry facilities, automated gaseous fire extinguishing is widely used. The main fire-extinguishing agents in automated gaseous fire-extinguishing systems are refrigerants HFC 23, 125, 227еа, FC 318c, and fluorinated ketone FK 5-1-12. Upon the adoption of the international agreements on combating global warming, most fluorinated gaseous fire-extinguishing agents currently used for fire extinguishing fell under restrictions. The article indicates the importance of refrigerants HFC 23, 125, 227еа, and FC 318c, whose production volume must be reduced by 85 % by 2036 to ensure the required level of fire and explosion protection of oil and gas industry facilities. A method to reduce the volumes of used fluorinated alkanes by producing highly efficient fire-extinguishing mixtures, one of the components of which is an agent of high global warming potential (GWP) and the other is a chemical compound with a short atmospheric lifetime, has been proposed. Dibromomethane, which fully meets the latest environmental requirements, is to be considered a short-lived component. Based on the well-known kinetic data, the rates of elementary chemical reactions generated in the flame of the methane-oxygen mixture when contacting with refrigerants HFC 23, 227еа, and dibromomethane, have been calculated and compared. The efficiency of using dibromomethane to increase the fire-extinguishing efficiency of refrigerants HFC 23 and 227еа has been substantiated. An experimental determination of the minimum fire-extinguishing efficiency of the generated mixed compositions is conducted to confirm the correctness of theoretical calculations. The obtained mixed gaseous fire-extinguishing agents enable the reduction of the volume of high global warming potential refrigerants by 1.5–2 times. It has been also demonstrated that the obtained mixed compositions have no toxic impact on a human.

Evaluation of energy and nutrient content of fruit juices and similar beverages in Türkiye and their investigation in terms of sustainability

This study aims to evaluate the contents of fruit juices and similar beverages in the Turkish market and to examine them in line with the Sustainable Development Goals. Within the scope of the study, the researchers examined the label information of 187 fruit juices and similar beverages from 26 different brands in four different product types. It was determined that all fruit nectars (100%) and almost all fruit and flavored beverages contain added sugar (92.8% for fruit beverages and 70.0% for flavored beverages). It was further detected that 17.5% of fruit nectars and 20.3% of fruit beverages contain sweeteners. Moreover, more than 100% of the daily sodium requirement is met by consuming 100 ml of fruit juice, nectar, or beverages. It was determined that orange and apple juices, apricot, peach, and cherry fruit nectars, and peach, sour cherry, and orange fruit beverages contain more sugar than freshly squeezed fruit juices (p<0.05). The high-fructose syrup manufacturing industry produces large volumes of waste liquid containing various waste carbohydrates, which has a significant environmental impact. Greenhouse gas emission sources are also released to the environment in sugar production processes. On the other hand, it was determined that most of the products examined were packaged in Tetra Pak® packaging. More sustainable product supply chains are those that optimize the use of materials, water, and energy throughout their lifecycle while minimizing waste from products and used packaging. In light of the data obtained from this study, it would be useful for the fruit juice industry to make regulations to ensure sustainable production and consumption patterns in order to ensure a healthy and quality life at all ages.

Modeling of dynamic modes of a generalized pumping station with an asynchronous electric drive of centrifugal pumps

Transportation of large volumes of liquid to distribution pipelines is provided by transit facilities - main pipelines and pumping stations, which consume significant amounts of electricity and are of strategic importance. The requirements for continuity, reliability, safety, fault finding, and diagnosis of existing, as well as requirements for the design of new strategic objects, are usually regulated by national legislation. The possibility of conducting physical experiments to analyze the modes of operation of such complexes is significantly limited by the inadmissibility of interrupting their functioning, as well as technical and financial risks. The use of a hybrid model consisting of a digital model of the power equipment and a physical model of the control system makes it possible to solve this problem. In this work, attention is focused on the digital model of power equipment. Based on the system approach and the principle of electrohydrodynamic analogy, a formalized mathematical model of the generalized system of asynchronous centrifugal pump units of a multi-unit pumping station with asynchronous electric drive of centrifugal pumps was created. The use of the principle of electrohydraulic analogy made it possible to apply the basic principles of the theory of electric circuits to form the equations of the hydraulic subsystem. The achieved formalization makes it possible to automate the formation of equations to obtain a model of an object of a specific configuration. The use of pump parameters in the model, which depend on the geometry of the internal elements, the speed of the impeller, and the physical properties of the liquid, makes it possible to investigate the impact of emergency and operational deviations of the equipment characteristics on the operating modes both at the level of individual modules and at the level of the pumping station as a whole. The obtained mathematical model was verified by adapting it to the pumping station of the given configuration. A computer simulation of several operational and emergency modes of operation of a pumping station with four hydraulically connected pumps was carried out. The scope of use and ways of improving the developed model are proposed, as well as the direction of further research

Eddy Current Flow Meter Measurements in Liquid Sodium at High Temperatures

Abstract We present measurement results for the flow rate of liquid sodium at temperatures up to 700 °C that were obtained with a high-temperature prototype of an immersed eddy current flow meter. The experimental campaign was conducted at the SOLTEC-2 sodium loop at KIT. The main objective of the experiments is the high-temperature qualification of the Eddy Current Flow Meter as part of the safety instrumentation of generation IV liquid metal-cooled fast reactors. There it is intended to be used for monitoring the flow rate of the coolant and to detect possible blockages of subassemblies. Due to the large liquid metal volume, the sensor has to be located close to the subassemblies, therefore measurements from outside of the vessel are not possible and an immersed sensor is required. We demonstrate the successful application of the immersed eddy current flow meter (ECFM) at such high temperatures and identify the relevant effects with impact on the sensor performance.

Characterization of the TruSense S310 laser range system for contact-less measurement of liquid levels in large-volume neutrino detectors

Neutrino experiments often use large volumes of water, organic scintillators or noble liquids as active detection material. Due to the large hydrostatic and buoyancy forces involved, precise knowledge of the liquid levels inside the detector tank are mandatory. Here we present the main characteristics of the TruSense S310 Laser Range System. Level measurements can be performed without direct contact to the liquid and through a gas-proof acrylic window, thus preserving the strict radiopurity and chemical requirements of the target liquid. We report the results of a suit of laboratory experiments for short-term precision tests (±5 mm) and long-term stability studies. Moreover, we demonstrate that the infrared laser can be used while standard bi-alkali PMTs are operational. We discuss the mechanical layout and integration of the system in the OSIRIS pre-detector that will monitor the radiopurity of the liquid scintillator for the large-volume neutrino experiment JUNO.

Raising the Dead Volume: Analysis of Microsamples Diluted and Corrected with Near Infrared Tracer.

Sample processing robotics require large liquid volumes to operate efficiently. Robotics are impractical in settings that deal in small specimen volumes such as pediatric laboratories. Short of manual sample handling, remedies for the current state include a redesign of current hardware or specialized adaptation for submilliliter specimens. We blindly increased the volume of plasma specimens with diluent containing a near infrared dye, IR820, to assess the change to the original specimen volume. Diluted specimens were analyzed using a variety of assay formats/wavelengths (sodium, calcium, alanine aminotransferase, creatine kinase, cholesterol, HDL cholesterol, triglyceride, glucose, total protein, creatinine), and results were compared to neat specimens. Recovery of analyte in the diluted specimens vs neat was the primary outcome measure. Mean analytic recovery from the diluted specimens across all assays ranged from 93% to 110% after correction using IR820 absorbance. Absorbance correction compared favorably to mathematical correction using known volumes of specimens and diluents (93%-107%). Pooled mean analytic imprecision across all assays ranged from 2% using the neat specimen pool to 8% when plasma pool was diluted to 30% of its original concentration. No interference from dye addition was noted, indicating the diluent was broadly applicable and chemically inert. The greatest variability in recovery was observed when respective analyte concentrations were present near the lower limits of assay detectability. Addition of a chemically inert diluent containing a near-infrared tracer is a feasible way to raise specimen dead volume and potentially automate processing and measurement of clinical analytes in microsamples.

HCOO− aq degradation in droplets by OHaq in an atmospheric pressure glow discharge

Plasmas in contact with liquids can degrade organic molecules in a solution, as reactive oxygen and nitrogen species produced in the plasma solvate into the liquid. Immersing small droplets (tens of microns in diameter) in the plasma can more rapidly activate the liquid compared to treating a large volume of liquid with a smaller surface-to-volume ratio. The interactions between a radio frequency glow discharge sustained in He/H2O and a water droplet containing formate (HCOO− aq) immersed in and flowing through the plasma were modeled using a zero-dimensional global plasma chemistry model to investigate these activation processes. HCOO − aq interacts with OHaq, which is produced from the solvation of OH from the gas phase. The resulting HCOO − aq concentrations were benchmarked with previously reported experimental measurements. The diameter of the droplet, initial HCOO − aq concentration, and gas flow rate affect only the HCOO − aq concentration and OHaq density, leaving the OH density in the gas phase unaffected. Power deposition and gas mixture (e.g. percentage of H2O) change both the gas and liquid phase chemistry. A general trend was observed: during the first portion of droplet exposure to the plasma, OHaq primarily consumes HCOO − aq. However, O2 − aq, a byproduct of HCOO − aq consumption, consumes OHaq once O2 − aq reaches a critically large density. Using HCOO − aq as a surrogate for OHaq-sensitive contaminants, combinations of residence time, droplet diameter, water vapor density, and power will determine the optimum remediation strategy.

Current Scenario of Hydrogel as Drug Delivery System

Crosslinked polymer networks known as hydrogels are capable of absorbing large volumes of water liquids. Depending on whether the crosslink connections are chemical or physical, hydrogels can be categorised into two groups. Physical networks feature temporary junctions that result from either polymer chain entanglements or physical interactions like ionic contacts, hydrogen bonds, or hydrophobic interactions, as opposed to chemically crosslinked networks, which have permanent junctions. Swellable polymeric polymers called hydrogels have received a lot of attention as potential drug delivery system carriers. These biomaterials have drawn attention because of their unusual properties, such as swelling in aqueous media, sensitivity to pH and temperature, or sensitivity to other stimuli. Because they are made of biocompatible materials, hydrogels are known to protect drugs from the in vivo environment, particularly peptides and proteins. Moreover, these swelling polymers are useful as tissue-specific targetable carriers for bioactive medicines. This article provides a summary of the developments in hydrogel-based drug delivery that have captured the attention of the majority of researchers.

Mass-production of water-based ferrofluids capable of developing spike-like structures

Ferrofluids are among the most popular and engaging materials related to the nanotechnology field, with applications ranging from studies of basic science phenomena to educational and outreach activities. Therefore, there is a continuous interest in the synthesis strategies used to fabricate these systems, especially those that can lead to simple procedures able to be reproduced under a wide spectrum of laboratory conditions.The ferrofluids described in this work are systems composed of iron oxide nanoparticles synthesized by the coprecipitation method and functionalized with citrate molecules to ensure the dispersion in an aqueous medium. During the experimental work we evaluated different operations and synthesis conditions, in order to arrive to a unique procedure that optimizes the functionalization results and the scaling potential. The optimized synthesis route has two main features that are worth to highlight. The first is the possibility of using readily available commercial products as chemical precursors; the second is the overall reduction of the procedure difficulties, as we show that several operations that are usually used in similar reports can be avoided, such as sonication, centrifugation, dialysis, inert atmospheres of Ar/N2 or heating of large volumes of liquid. Both features can be included in the synthesis route without compromising the ferrofluid quality. The procedure can be used to successfully prepare nearly 30 g of functionalized nanoparticles per synthesis batch. Furthermore, this production has the potential to increase due to the absence of significant limitations in the scaling process.We show that the synthesized nanoparticles can produce a stable colloid even at extremely high concentrations (above 50% wt), leading to the formation of ferrofluids that can develop static peak patterns, known as Rosensweig instabilities, when exposed to an external magnetic field. In turn, we show that the extent of these disturbances can be modified both with the concentration of nanoparticles and with the surface tension of the ferrofluid, as expected for this type of system.

Quantitative chemical assay of nanogram-level particulate matter using aerosol mass spectrometry: characterization of particles collected from uncrewed atmospheric measurement platforms

Abstract. Aerosol generation techniques have expanded the utility of aerosol mass spectrometry (AMS) for offline chemical analysis of airborne particles and droplets. However, standard aerosolization techniques require relatively large liquid volumes (e.g., several milliliters) and high sample masses that limit their utility. Here we report the development and characterization of a micronebulization AMS (MN-AMS) technique that requires as low as 10 µL of sample and can provide the quantification of the nanogram level of organic and inorganic substances via the usage of an isotopically labeled internal standard (34SO42-). Using standard solutions, the detection limits for this technique were determined at 0.19, 0.75, and 2.2 ng for sulfate, nitrate, and organics, respectively. The analytical recoveries for these species are 104 %, 87 %, and 94 %, respectively. This MN-AMS technique was applied successfully to analyze filter and impactor samples collected using miniature particulate matter (PM) samplers deployable on uncrewed atmospheric measurement platforms, such as uncrewed aerial systems (UASs) and tethered balloon systems (TBSs). Chemical composition of PM samples collected from a UAS field campaign conducted at the Department of Energy's (DOE) Southern Great Plains (SGP) observatory was characterized. The offline MN-AMS data compared well with the in situ PM composition measured by a co-located aerosol chemical speciation monitor (ACSM). In addition, the MN-AMS and ion chromatography (IC) agreed well for measurements of sulfate and nitrate concentrations in the PM extracts. This study demonstrates the utility of combining MN-AMS with uncrewed measurement platforms to provide quantitative measurements of ambient PM composition.

Commercialization of Ionic Liquids in Pursuit of Green Chemistry: Must we Each Become an Entrepreneur?

There will be common challenges to scaling-up any ionic liquids separations technologies which require very large volumes of ionic liquid. Some of these challenges are illustrated in this personal account which chronicles the extraction of chitin from shrimp shell from discovery to current commercialization efforts. The road being taken from discovery in an academic laboratory, through attempts to navigate the scaling-up to commercial scale using the vehicle of a faculty startup company is rewarding, but fraught with roadblocks, detours, and unexpected challenges. The differences in 'technically feasible' and 'commercially viable' are not always evident from the beginning of the journey, however, one wonders what achievements we miss as a Society because it was assumed to not be commercially viable.

Experimental Analysis of the Flow Characteristics of an Adjustable Critical-Flow Venturi Nozzle

The response of an adjustable critical-flow Venturi nozzle is investigated through a set indoor experiments aimed to determine the related critical flow rate, critical pressure ratio, and discharge coefficient. The effect of a variation in the cone displacement and liquid content on the critical flow characteristics is examined in detail and it is shown that the former can be used to effectively adjust the critical flow rate. The critical pressure ratio of the considered nozzle is above 0.85, and the critical flow control deviation of the gas flow is within ±3%. Liquid flow can reduce the gas critical mass flow rate accordingly, especially for the cases with larger liquid volume and lower inlet pressure. The set of results and conclusions provided are intended to support the optimization of steam injection techniques in the context of heavy oil recovery processes.

Chemical engineering kinetics of p-xylene chlorination in a gas-liquid agitated reactor

This study aims at determining both the rate constants of chlorination of p-xylene with molecular chlorine and FeCl3 as a catalyst at 70 °C and 90 °C and the related chemical engineering parameters to be used in the design of an effective chemical reactor.This was accomplished by a novel approach of constructing a linear mathematical function for a gas–liquid semi-batch agitated reactor correlating all engaged physical and chemical factors. Collecting values for all the necessary parameters for the application of the function, or in the absence of them calculating them, and exploiting the intercept and slope of the linear function became possible the apparent and the catalytic reaction rate constants to be calculated. It was found that the calculated values were of the same order of magnitude as values obtained by other researchers.The parameters needed to be calculated were Henry’s constant, the diffusion coefficient of the solute A (chlorine) to the solvent B (p = xylene), DAB, and the mean liquid phase mass transfer coefficient, kl. Other parameters of chemical engineering interest were also determined, namely, the interface per unit volume of liquid, a, the thickness of the liquid film, δl, and the Hatta number, MH.Evaluating the Hatta number estimated, it was concluded that the chlorination of p-xylene with molecular chlorine is very slow at both temperatures investigated, and almost no reaction occurs in the film compared to the bulk of the liquid. Thus, to increase the overall reaction rate, a large volume of liquid is needed while the increase of agitation intensity is of no value here.Combining the rate constant ratios obtained recently for the four consecutive second-order irreversible chlorinations of p-xylene with molecular chlorine with FeCl3 as a catalyst at 70 °C and under identical conditions it was possible to determine the values of all rate constants up to the fourth chlorinated product.

Development of ionic liquid circulation system in high-vacuum chamber for semiconductor device fabrication

In this study, a high-vacuum-compatible liquid circulation system was developed using an ionic liquid with a very low vapor pressure as the working fluid. The rationale for the development of this device is the increasing need for wet processing under vacuum conditions for application to semiconductor fabrication, such as developing and rinsing. Wet processes generally use a large volume of liquid; therefore, they need to be conducted under atmospheric pressure. However, vacuum-compatible wet processes are desirable because high vacuum is beneficial for cleanliness and use of beam progression in fabrication processes. Therefore, a liquid circulation system that can be directly used under a high vacuum is needed. The system developed in this study can circulate over 100 mL ionic liquid under direct vacuum exposure, regardless of the inner chamber pressure. The usefulness of a prototype of this system was experimentally investigated. The system reached an ultra-high vacuum pressure of 10−5 Pa. Outgassed ionic liquid fragments were detected with low partial pressures of the order of <10−6 Pa. We concluded that this device can be exploited for semiconductor fabrication application.

Proton-detected solution-state NMR at 14.1 T based on scalar-driven 13C Overhauser dynamic nuclear polarization

Overhauser dynamic nuclear polarization (ODNP) NMR of solutions at high fields is usually mediated by scalar couplings that polarize the nuclei of heavier, electron-rich atoms. This leaves 1H-detected NMR outside the realm of such studies. This study presents experiments that deliver 1H-detected NMR experiments on relatively large liquid volumes (60 ∼ 100 μL) and at high fields (14.1 T), while relying on ODNP enhancements. To this end 13C NMR polarizations were first enhanced by relying on a mechanism that utilizes e--13C scalar coupling interactions; the nuclear spin alignment thus achieved was then passed on to neighboring 1H for observation, by a reverse INEPT scheme relying on one-bond JCH-couplings. Such 13C →1H polarization transfer ported the 13C ODNP gains into the 1H, permitting detection at higher frequencies and with higher potential sensitivities. For a model solution of labeled 13CHCl3 comixed with a nitroxide-based TEMPO derivative as polarizing agent, an ODNP enhancement factor of ca. 5x could thus be imparted to the 1H signal. When applied to bigger organic molecules like 2-13C-phenylacetylene and 13C8-indole, ODNP enhancements in the 1.2-3x range were obtained. Thus, although handicapped by the lower γ of the 13C, enhancements could be imparted on the 1H thermal acquisitions in all cases. We also find that conventional 1H–13C nuclear Overhauser enhancements (NOEs) are largely absent in these solutions due to the presence of co-dissolved radicals, adding negligible gains and playing negligible roles on the scalar e-→13C ODNP transfer. Potential rationalizations of these effects as well as extensions of these experiments, are briefly discussed.