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The mineralization of fluoroelastomers (FKMs) in superheated water in the presence of potassium hydroxide (KOH) was investigated with the aim of developing a methodology for recycling the fluorine element. Two FKMs—an "uncrosslinked FKM", representing a poly(vinylidene fluoride-co-hexafluoropropylene) (poly(VDF-co-HFP)) copolymer with a VDF/HFP molar ratio of 78/22 and a "crosslinked FKM" consisting of this copolymer (cured by peroxide) and carbon black—were treated. The fluorine content of these FKMs was efficiently transformed into F− ions in the reaction solution using low KOH concentrations (0.10–0.50 M) at 200–250 °C. When the uncrosslinked or crosslinked FKMs reacted with aqueous KOH (0.20 M) at a rather low temperature (200 °C) for 18 h, the fluorine content of these FKMs was completely mineralized (both F− yields were 100%). Although the crosslinked FKM contained carbon black, the fluorine mineralization of the FKM was not inhibited. The addition of Ca(OH)2 to the reaction solutions after the superheated water treatment at 250 °C for 6 h with aqueous KOH (0.50 M) led to the production of pure CaF2, identified using X-ray spectroscopy, with 100% and 93% yields for the uncrosslinked and crosslinked FKMs, respectively. [ABSTRACT FROM AUTHOR]

The article presents the results obtained from a complex study of heavily superheated water atomization during its discharging through various types of atomizers. A system for optic measurements of the spray cone dispersion structure has been developed and adjusted. The developed measurement system is based on measuring the scattering indicatrix of a probing laser emission in a wide range of angles (±45°) and solving the inverse scattering problem using the Mie theory. The results from a wide-scale experimental study of the spray cone dispersion structures produced by various types of nozzles with a sprayed water temperature of 140‒260°С and pressure at the nozzle exit equal to 0.1 MPa are presented, and the possibility of liquid atomization (to water droplets with a diameter of 5 µm or smaller down to submicrometer size) at high temperatures is shown. It has been found that the spray cone structure has a pronounced bimodal pattern: droplets 5‒8 µm in diameter combine with a submicrometer mode. With a growth of atomized water temperature, the fraction of submicrometer mode increases, reaching 60‒65 wt % at a temperature of 240‒260°С for cylindrical nozzles and 80‒90 wt % for convergent-divergent nozzles. For the case of water injection into the compressor of a gas turbine unit equipped with the TV-117 industrial grade turbine, the possibility of additionally controlling the peak power output has been demonstrated. It makes 4–8% per water flowrate percent (with respect to the air flowrate). The power output control quality is in compliance with the requirements of the UES of Russia network standards. Superheated water is finding an increasingly growing use for firefighting at power industry facilities, in closed premises, in spills of petroleum products, in performing operations with liquefied gas, and in other situations. [ABSTRACT FROM AUTHOR]

Hydrogen is considered as the future energy vector. Due to scarceness in materials, obtaining hydrogen from common metals and metallic residues is gaining interest. The present work aims at coupling for the first time solvent-based CO 2 capture processes with the hydrogen generation from the metal-water splitting reaction, using common elements such as Al, Zn, Mn and Fe. To do so, a novel semicontinuous facility is developed. In the process, both the CO 2 -Rich stream (CO2RS) and CO 2 Capture-Solvent Lean stream (CO2LS) are considered. The production of H 2 increased in the order Al < Mn < Fe < Zn. For pure Al, aqueous NaOH (CO2LS) showed the highest H 2 yield, up to 85.5%, while Al chips (residue) showed outstanding performance. The experimental study showed that small particle sizes improve the H 2 yield. This technology represents an opportunity for bringing about value-added to CO 2 capture by generating at the same time green hydrogen. [Display omitted] • A novel semicontinuos facility was designed for H 2 generation from water-splitting. • Aqueous NaOH promoted the highest H 2 yield of 85.5%. • H 2 yield increased in the order Al < Mn < Fe < Zn, using ammonium carbamate as CO2RS. • Most basic CO2RSs and CO2LSs produce a bigger effect with larger metal-particles. • H 2 generation with Al and NaOH proceeded in a self-sustaining way at room temperature. [ABSTRACT FROM AUTHOR]

The article deals with the problem of increasing the efficiency and competitiveness of the underground coal gasification technology at the expense of utilizing the thermal energy of the underground gas generator, which is lost in the bowels. The authors have been analyzing the suggested by them system "variable phase turbine (VPT) - well recuperator". It could be included into the thermal circuit of the underground coal gasification and be capable of utilizing up to 30% of thermal energy losses of the gas generator, providing high efficiency of electricity generation from a low-grade heat carrier. The idea of using a powerful VPT (up to 100 kW) and corresponding recuperators for a downhole gas generator and the formation of a coal gasification zone along a single well has been a technical innovation which is to be substantiated. To realize this task the authors have developed a certain algorithm for the thermal calculation of convective heat transfer from the "well-gas generator" to the recuperator with a water heat carrier Thus the quantitative assessment of the thermal efficiency which could be obtained from a single heat removal well, has been carried out. The technical parameters of a high power VPT within the thermal circuit of underground coal gasification have been substantiated and could have been realized. Alongside, it become possible to do the calculations for the flow characteristics, the traction jet force, the consumed heat power during the turbine operation and at last for the efficiency and carnotization factor. Such calculations have been successfully carried out. [ABSTRACT FROM AUTHOR]

The atomization of metastable superheated water injected into the atmosphere through a convergent-divergent nozzle at a temperature of 240–260°C was studied experimentally. The dispersion structure of the atomization plume is bimodal with a predominance of submicron droplets, whose proportion increases with increasing temperature and reaches 80% at the nozzle outlet at a water temperature of 260°C. The influence of droplet coagulation on the distribution of the proportion of large droplets along the length of the atomization plume was estimated. [ABSTRACT FROM AUTHOR]

Liquid water is the most intriguing liquid in nature, both because of its importance to every known form of life, and its numerous anomalous properties, largely magnified under supercooled conditions. Among the anomalous properties of water is the seeming divergence of the thermodynamic response functions and dynamic properties below the homogenous nucleation temperature (~ 232 K). Furthermore, water exhibits an increasingly decoupling of the viscosity and diffusion, upon cooling, resulting in the breakdown of the Stokes-Einstein relationship (SER). At high temperatures and pressures, however, water behaves more like a "simple" liquid. Nonetheless, experiments at 400 K and GPa pressures (Bove et al. (2011) Phys. Rev. Lett., 111:185,901) showed that although the diffusion decreases monotonically with the pressure, opposite to pressurized supercooled water, a decoupling of the viscosity and diffusion, larger than that found in supercooled water at normal pressure, is observed. Here, we studied the validity of SER and different pressure-dependent thermodynamic response functions, known to exhibit an abnormal behavior upon cooling, including the density, isothermal compressibility, and the thermal expansion coefficient along the 400 K isotherm up to 3 GPa through molecular dynamics simulations. Seven different water models were investigated. A monotonic increase of the density (~ 50%) and decrease of the isothermal compressibility (~ 90%) and thermal expansion (~ 65%) is found. Our results also show that compressed hot water has various resemblances to cool water at normal pressure, with pressure inducing the formation of a new second coordination sphere and a monotonic decrease of the diffusion and viscosity coefficients. Whereas all water models provide a good account of the viscosity, the magnitude of the violation of the SER at high pressures (> ~ 1 GPa) is significantly smaller than that found through experiments. Thus, violation of the SER in simulations is comparable to that observed for liquid supercooled water, indicating possible limitations of the water models to account for the local structure and self-diffusion of superheated water above ~ 1 GPa. [ABSTRACT FROM AUTHOR]

• MIDI: an integral-scale experiment of a light-water-reactor spent fuel pool. • A study of the influence of the spent fuels loading pattern, decay heat and initial pool level on the thermal-hydraulics of a spent fuel pool under loss-of-cooling accident conditions, before the spent fuels get uncovered. • A phenomenology which is characterized by three competing liquid vaporization modes: the evaporation at the pool free surface, the nucleate boiling within the fuel bundles and the gravity-driven flashing of superheated water on top of the storage racks. • The existence of the gravity-driven flashing of superheated water is confirmed in the configuration of a spent fuel pool. This article provides a first interpretation of the MIDI tests that were conducted in the frame of the IRSN's DENOPI project. A first-level phenomenological analysis is detailed here. It is shown that the actual phenomenology mostly complies with the one that was envisioned by the community right after the Fukushima-Daiichi nuclear accident. Next, the diverse modes of water vaporization that may come into play during a spent nuclear fuel pool loss-of-cooling accident are quantified for each achieved test, by means of a proposed analytical model of the vapor diffusion process taking place on top of the liquid pool free surface. Then, a so-called vaporization regimes map is reconstructed on the basis of the test data. This map allows predicting the most likely dominant vaporization mode, given the pool level and total heat power. At last, the obtained data is reduced through the form of a set of dimensionless correlations, involving some of the classical numbers in heat and mass transfers. In doing so, the free surface evaporation, degassing of dissolved gaseous species and bubbles release processes are all modeled by means of a simple mathematical formulation. [ABSTRACT FROM AUTHOR]

• MIDI: an integral-scale experiment of a light-water-reactor spent fuel pool. • A study of the influence of the spent fuels loading pattern, decay heat and initial pool level. • A phenomenology which is characterized by three competing liquid vaporization modes. • The gravity-driven flashing is accidentally likely in a spent fuel pool. Motivated by the 2011 accident at the Fukushima Daiichi nuclear power station, the French Institute for Radiation Protection and Nuclear Safety (IRSN) launched in 2014 the DENOPI project. This research program, supported by the French Government and carried out in collaboration with national and international partners, dealt with the open issues of spent fuel pool accidents. As part of this project, a test facility named MIDI was designed and built at the IRSN's research unit of Cadarache, France. The MIDI facility is an experimental tool which aims at reproducing the thermal–hydraulic phenomena that may occur at an integral scale in a spent fuel pool undergoing a loss-of-cooling accident, before the stored fuels get uncovered. This paper first describes the MIDI facility and its instrumentation and the test matrix achieved to date. An overview of its main results is then provided. In the framework of the DENOPI project, nine tests were achieved and allowed investigating the phenomenology of this type of accident. The highlighted phenomenology is characterized by three competing liquid vaporization modes: the evaporation at the pool free surface, the nucleate boiling within the fuel bundles and the gravity-driven flashing of superheated water on top of the storage racks. The existence of the latter vaporization mode, uncertain at the launch of the DENOPI project, is now confirmed in the configuration of a spent fuel pool. [ABSTRACT FROM AUTHOR]

The mineralization of fluoroelastomers (FKMs) in superheated water in the presence of potassium hydroxide (KOH) was investigated with the aim of developing a methodology for recycling the fluorine element. Two FKMs—an “uncrosslinked FKM”, representing a poly(vinylidene fluoride-co-hexafluoropropylene) (poly(VDF-co-HFP)) copolymer with a VDF/HFP molar ratio of 78/22 and a “crosslinked FKM” consisting of this copolymer (cured by peroxide) and carbon black—were treated. The fluorine content of these FKMs was efficiently transformed into F− ions in the reaction solution using low KOH concentrations (0.10–0.50 M) at 200–250 °C. When the uncrosslinked or crosslinked FKMs reacted with aqueous KOH (0.20 M) at a rather low temperature (200 °C) for 18 h, the fluorine content of these FKMs was completely mineralized (both F− yields were 100%). Although the crosslinked FKM contained carbon black, the fluorine mineralization of the FKM was not inhibited. The addition of Ca(OH)2 to the reaction solutions after the superheated water treatment at 250 °C for 6 h with aqueous KOH (0.50 M) led to the production of pure CaF2, identified using X-ray spectroscopy, with 100% and 93% yields for the uncrosslinked and crosslinked FKMs, respectively.

In this study, a new device was used to inactivate G. stearothermophilus spores in ready-to-eat (RTE) poached spicy pork slices (PSPS) applying radio frequency (RF) energy (27.12 MHz, 6 kW) and superheated water (SW) simultaneously. The cold spot in the PSPS sample was determined. The effects of electrode gap and SW temperature on heating rate, spore inactivation, physiochemical properties (water loss, texture, and oxidation), sensory properties, and SEM of samples were investigated. The cold spot lies in the geometric center of the soup. The heating rate increased with increasing electrode gap and hit a peak under 190 mm. Radio frequency combined superheated water (RFSW) sterilization greatly decreased the come-up time (CUT) compared with SW sterilization, and a 5 log reduction in G. stearothermophilus spores was achieved. RFSW sterilization under 170 mm electrode gap reduced the water loss, thermal damage of texture, oxidation, and tissues and cells of the sample, and kept a better sensory evaluation. RFSW sterilization has great potential in solid or semisolid food processing engineering. [ABSTRACT FROM AUTHOR]

Fluorinated ionic liquids are cutting-edge materials investigated for electrolytic media for energy-related applications. Although their industrial usages are being spread, waste treatment techniques for these materials are not well established, because they are thermally and chemically stable, owing to the presence of strong carbon-fluorine bonds, and incineration produces hydrogen fluoride gas, which seriously damages incinerators. We describe herein our recent efforts to decompose fluorinated ionic liquids to F− ions (i.e., mineralization) by use of superheated water, with the aim for closing the loops on fluorine element. A methodology that enables complete mineralization of the ionic liquids bearing [(CF3SO2)2N]− anion moiety is demonstrated.

In this study, a new device was used to inactivate G. stearothermophilus spores in ready-to-eat (RTE) poached spicy pork slices (PSPS) applying radio frequency (RF) energy (27.12 MHz, 6 kW) and superheated water (SW) simultaneously. The cold spot in the PSPS sample was determined. The effects of electrode gap and SW temperature on heating rate, spore inactivation, physiochemical properties (water loss, texture, and oxidation), sensory properties, and SEM of samples were investigated. The cold spot lies in the geometric center of the soup. The heating rate increased with increasing electrode gap and hit a peak under 190 mm. Radio frequency combined superheated water (RFSW) sterilization greatly decreased the come-up time (CUT) compared with SW sterilization, and a 5 log reduction in G. stearothermophilus spores was achieved. RFSW sterilization under 170 mm electrode gap reduced the water loss, thermal damage of texture, oxidation, and tissues and cells of the sample, and kept a better sensory evaluation. RFSW sterilization has great potential in solid or semisolid food processing engineering.

In situ instrumentation that can detect amino acids at parts-per-billion concentration levels and distinguish an enantiomeric excess of either d- or l-amino acids is vital for future robotic life-detection missions to promising targets in our solar system. In this article, a novel chiral amino acid analysis method is described, which reduces the risk of organic contamination and spurious signals from by-products by avoiding organic solvents and organic additives. Online solid-phase extraction, chiral liquid chromatography, and mass spectrometry were used for automated analysis of amino acids from solid and aqueous environmental samples. Carbonated water (pH ∼3, ∼5 wt % CO2 achieved at 6 MPa) was used as the extraction solvent for solid samples at 150°C and as the mobile phase at ambient temperature for chiral chromatographic separation. Of 18 enantiomeric amino acids, 5 enantiomeric pairs were separated with a chromatographic resolution >1.5 and 12 pairs with a resolution >0.7. The median lower limit of detection of amino acids was 2.5 μg/L, with the lowest experimentally verified as low as 0.25 μg/L. Samples from a geyser site (Great Fountain Geyser) and a geothermal spring site (Lemon Spring) in Yellowstone National Park were analyzed to demonstrate the viability of the method for future in situ missions to Ocean Worlds. [ABSTRACT FROM AUTHOR]

• A main aerial severe pressure peak was produced with high anisotropy. • The boiling two phase jet released by the vessel reached 20 m. • Blast effect was not related with energy but with orifice size. • A first pressure peak was doubtless created by the pre-existing vapour expansion. • A second peak happened during intense boiling phase. A boiling liquid expanding vapour explosion (BLEVE) is a physical explosion caused by a sudden rupture of a vessel containing superheated liquid. A BLEVE can occur with many types of fluids and is not an exclusive phenomenon for flammable liquefied gases such as propane or butane. Other superheated liquids suffering a fast depressurization at high temperature may entail a BLEVE, such as water in steam generation systems. Several pieces in literature suggest that superheated water may produce a BLEVE, but little experimental data can be found on that topic. The aim of this work was to perform water BLEVE tests with a 14 L pressure vessel designed on purpose to produce high superheated liquid water (290 °C; 75 bar) and to trigger a BLEVE through calibrated rupture disks. Pressure sensors were set in the vessel to measure the internal phase change pressure dynamics and other aerial overpressure sensors were put around the relief rupture disk to capture the blast wave. Temperature of water was also recorded, and a fast camera (Phantom V2512) was used to see the phenomenon. Data show clearly the pressure recovery due to rapid boiling in the vessel. Explosive boiling did not add additional internal pressure force on the containment. Two main blast waves were observed, they were strongly related with outlet orifice area but little dependant on filling ratio. The two phase jet reached a 20 m range. [ABSTRACT FROM AUTHOR]

The structure and properties of bio‐based polyamide 109 (PA109) after treatment with superheated water (140 °C ≤ T ≤ 280 °C) were investigated and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, wide‐angle X‐ray diffraction, scanning electron microscopy and small‐angle X‐ray scattering. Below 170 °C, the hydrothermal treatment was considered to be a physical process, which exerted an annealing effect on PA109. It led to an increase in melting temperature, lamellar thickness and crystallinity, while the macromolecular structure, crystal structure and the order of crystalline regions were not affected. Above 170 °C, complete melting/dissolution of PA109 occurred with partial hydrolysis. Due to the high temperature and long reaction time, the hydrolysis reaction became more and more prominent, and the resin was completely hydrolyzed into oligomers at 280 °C. Also, above 170 °C, the hydrothermal treatment was accompanied by a chemical process and the melting temperature and molecular weight decreased progressively. Notably, the crystal structure was not altered, but the degree of perfection of crystals and the order of crystalline regions were broken, especially above 200 °C. The hydrolytic degradation reaction was significantly affected by temperature, while both time and the water to polyamide ratio were secondary factors which influenced it to a minor extent. The process could be considered as a typical nucleophilic substitution reaction which takes place step by step inducing the molecular weight to decrease gradually. Overall, this study provides a 'green' route for the processing, recycling and treatment of environmentally friendly polyamides based on hydrothermal treatment technology. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract This work aimed to evaluate the feasibility of subcritical water-hydrolyzed pectin from passion fruit (Passiflora edulis) peel for improving emulsifying property of whey protein at pH near its isoelectric point. The hydrolyzed pectin with different molecular weights (20, 77, and 146 kDa) were conjugated with whey protein isolate by a dry-heating method at 80 °C, 79% RH, for 6, 24, and 48 h. Soluble fraction after the conjugation was analyzed for conjugated molecules by SDS-PAGE and fluorescence spectroscopy. SDS-PAGE showed polydisperse bands from 15 to 250 kDa, which indicated that whey protein isolate-pectin conjugates were formed. Fluorescence spectroscopy also revealed that the highest conjugates yield was obtained from the conjugation with 146 kDa pectin at 6 h. These conjugates were used as emulsifiers in oil-in-water emulsions containing 5% w/w of medium-chain triacylglycerol in an aqueous phase at pH of 5. The smallest oil-droplet size and most stable emulsion was also obtained using the conjugates at 6 h of the dry-heating. Moreover, the conjugates from larger pectins showed significantly higher emulsion stability. Graphical abstract Image 10971 Highlights • The conjugates were tested as emulsifiers and could give small oil-droplet sizes <1.0 μm. • Emulsions showed excellent stability albeit they were prepared at near pI of WPI. • The most stable emulsion was obtained using the conjugates at 6 h of dry-heating. [ABSTRACT FROM AUTHOR]

The modeling of thermal fluid (mostly reported for saturated steam) flow in wells involving steady-state heat transfer inside wellbores and transient heat transfer in sea water or formation is reviewed and inherited. It is a good addition of modeling of supercritical/superheated fluid to the existing body of literature. The flow of supercritical CO 2 coupled with superheated water (SHW) in offshore wells is described by means of the differential mass, energy and momentum balance equations along the vertical wellbores. The effect of supercritical CO 2 on pressure and temperature of the multi-component thermal fluid is expressed in terms of the real gas model (the S-R-K model). The differential equations are solved with finite difference method on space involving the constant injection parameters at wellhead. It is found out that: (a). while seawater has a significant influence on temperature drop in wellbores, its effect on pressure profiles is weak. (b). both temperature and superheat degree decrease with increasing of the content of supercritical CO 2 . Besides, study of the effect of injection rate and pressure is conducted. [ABSTRACT FROM AUTHOR]

This paper examines a novel method of regenerating saturated activated carbon after adsorption of complex phenolic, polycyclic aromatic hydrocarbons with low energy consumption by using superheated water pretreatment combined with CO2 activation. The effects of the temperature of the superheatedwater, liquid-solid ratio, soaking time, activation temperature, activation time and CO2 flow rate of regeneration and adsorption of coal-powdered activated carbon (CPAC)were studied. The results show that the adsorption capacity of iodine values on CPAC recovers to 102.25% of the fresh activated carbon and the recovery rate is 79.8%under optimal experimental conditions. The adsorptionmodel and adsorption kinetics of methylene blue on regenerated activated carbon (RAC) showed that the adsorption process was in accordance with the Langmuir model and the pseudo-second-order kinetics model. Furthermore, the internal diffusion processwas themain controlling step. The surface properties, Brunauer-Emmett-Teller (BET) surface area and pore size distribution were characterized by Fourier transform infrared spectroscopy (FT-IR) and BET, which show that the RAC possesses more oxygencontaining functional groups with a specific surface area of 763.39m2 g-1 and a total pore volume of 0.3039 cm3 g-1. Micropores account for 79.8% and mesopores account for 20.2%. [ABSTRACT FROM AUTHOR]

The ever-increasing demand for determining compounds at low concentration levels in complex matrices requires a preliminary step of analytes isolation/enrichment in order to employ a detection technique characterized by high sensitivity at low LOQ. Sample preparation is considered as crucial part of analytical procedures. Previously the parameter of “greenness” is as important as selectivity in order to avoid using harmful organic solvents in sustainable extraction techniques. These solvents can generate hazardous, toxic waste while consuming large resources volume. Developing new green solvents is one of the key subjects in Green Chemistry in order to reduce the intensity of anthropogenic activities related to analytical laboratories. A lot of new, more eco-friendly media have been employed as extractant phases. These media, besides of being more eco-friendly, provide shorter extraction times, simplicity, low cost, better selectivity in some cases. The most promising, most widely used green extraction solvents are described in this review. [ABSTRACT FROM AUTHOR]

It is known that aqueous keratin hydrolysate solutions can be produced from feathers using superheated water as solvent. This method is optimized in this study by varying the time and temperature of the heat treatment in order to obtain a high solute content in the solution. With the dissolved polypeptides, films are produced using methyl cellulose as supporting material. Thereby, novel composite membranes are produced from bio-waste. It is expected that these materials exhibit both protein and polysaccharide properties. The influence of the embedded keratin hydrolysates on the methyl cellulose structure is investigated using Fourier transform infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). Adsorption peaks of both components are present in the spectra of the membranes, while the X-ray analysis shows that the polypeptides are incorporated into the semi-crystalline methyl cellulose structure. This behavior significantly influences the mechanical properties of the composite films as is shown by tensile tests. Since further processing steps, e.g., crosslinking, may involve a heat treatment, thermogravimetric analysis (TGA) is applied to obtain information on the thermal stability of the composite materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • PVDF efficiently decomposed to F– in superheated water with KOH at 250 °C under Ar. • The F− yield reached 95 % and quasi-complete mineralization was achieved. • The mineralization was accompanied by the formation of amorphous carbon. • Poly(VDF- co -HFP) and ETFE copolymers also completely decomposed to F−. • Addition of Ca(OH) 2 to the reaction solutions of these (co)polymers formed pure CaF 2. Mineralization of poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride- co -hexafluoropropylene) [poly(VDF- co -HFP)] copolymer, and poly(ethylene- co -tetrafluoroethylene) copolymer (ETFE) in superheated water in the presence of an alkaline reagent was investigated with the aim of developing a technique to recycle the fluorine element. These polymers underwent almost complete defluorination to form fluoride ions (F–) in the reaction solution at a relatively low temperature (250 °C) under Ar atmosphere. When PVDF was reacted with aqueous KOH (1.0 M) for 6 h, the amount of which corresponds to 10 times the molar amount of fluorine content (as atoms) in PVDF, the yield of F– released into the reaction solution reached 95 %. This transformation was accompanied by the formation of carbon rich reside, which consists of amorphous carbon. In contrast, for a treatment performed with O 2 instead of Ar, significant differences were observed in the products: while F– ions efficiently produced in the reaction solution, carbon rich residue did not form and the major species that composed the total organic carbon content in the reaction solution was oxalate. Four consecutive runs (that is, after one reaction at 250 °C under Ar was complete, new PVDF was charged to the reaction mixture and then reacted again) caused no decrease of the F– yield. When treated with aqueous KOH (1.0 M) under Ar at 250 °C for 6 h, poly(VDF- co -HFP) and ETFE copolymers also completely mineralized to form F– ions with 100 and 98 % yields, respectively. Introducing Ca(OH) 2 to the resulting reaction solutions of these (co)polymers after superheated water treatment produced pure CaF 2 , i.e., artificial fluorspar. [ABSTRACT FROM AUTHOR]

The aim of this study was to optimize the conditions for subcritical water treatment of krill, as expressed with a single parameter: the severity factor (log R0). Raw krill was treated under subcritical water conditions at various log R0values (1.54–3.75) by varying the treatment temperatures (120–180 °C) and times (0–10 min) in two different sizes of batch-type vessel (10 and 117 mL). The log R0value could efficiently describe changes in various properties of the obtained liquid extracts and solid residues. The most desirable shrimp-like flavor intensity and highest sensory preference were obtained for log R0values of 2.75–3.01. The results also proved that severity factor can be used as a single parameter to control subcritical water treatment conditions in differently sized batch-type vessels to produce shrimp-like flavor extract and residue from krill. Optimization of krill treatment under subcritical water conditions. [ABSTRACT FROM PUBLISHER]

A novel and environmentally benign protocol for the synthesis of amines from cyclic ketones and formamides is demonstrated. The reaction proceeds under catalyst-free and superheated water conditions and yields range from poor to excellent. [ABSTRACT FROM AUTHOR]

Monodisperse porous poly(glycidylmethacrylate- co -ethylenedimethacrylate) (poly(GMA- co -EDMA) beads) with a diameter of 3 μm each were custom synthesized by a single-step swelling and polymerization method. Small sizes (1.2 μm) with polystyrene seed templates of low molecular weight were prepared by the addition of 1,1-diphenylethylene to control the polymerization reaction. Polystyrene seed particles were swollen directly by a mixture of methacrylate monomers and porogen. By swelling polystyrene seed particles with tetrahydrofuran as the porogen, a surface area of 108 m 2 g −1 was achieved. The porous polymer microspheres were evaluated as stationary phase for liquid chromatography using superheated water as a mobile phase. Chromatographic performance at different temperatures was studied, along with analyte and column stability. The results confirm that the particles were stable under superheated water conditions. There was almost no change to the retention properties during the 160 sequential injections of a standard mixture (uracil, pyridine, phenol, dimethyl phthalate and N,N-dimethylaniline) at 150 °C. The chromatographic peaks show good symmetry with an efficiency of up to 47,000 plates m −1 under realistic separation conditions. Thermal decomposition of analytes (aldicarb sulfone, oxamyl, aldicarb and benomyl) separated under different column temperatures, was evaluate. Chromatograms of pesticide standard mixtures separated in the temperature range of 100–140 °C displayed good separation. The detection limits of 1.2 and 1.6 mg L −1 for benomyl and aldicarb were obtained when the separation was performed at 120 °C with flow rate of 0.4 mL min −1 water. However these pesticides were decomposed at the separation temperature above 140 °C. [ABSTRACT FROM AUTHOR]