Evaporation Of Volatile Components Research Articles

Enhanced Light Absorption and Elevated Viscosity of Atmospheric Brown Carbon through Evaporation of Volatile Components.

Samples of brown carbon (BrC) material were collected from smoke emissions originating from wood pyrolysis experiments, serving as a proxy for BrC representative of biomass burning emissions. The acquired samples, referred to as "pyrolysis oil (PO1)," underwent subsequent processing by thermal evaporation of their volatile compounds, resulting in a set of three additional samples with volume reduction factors of 1.33, 2, and 3, denoted as PO1.33, PO2, and PO3. The chemical compositions of these POx samples and their BrC chromophore features were analyzed using a high-performance liquid chromatography instrument coupled with a photodiode array detector and a high-resolution mass spectrometer. The investigation revealed a noteworthy twofold enhancement of BrC light absorption observed for the progression of PO1 to PO3 samples, assessed across the spectral range of 300-500 nm. Concurrently, a decrease in the absorption Ångstrom exponent (AAE) from 11 to 7 was observed, indicating a weaker spectral dependence. The relative enhancement of BrC absorption at longer wavelengths was more significant, as exemplified by the increased mass absorption coefficient (MAC) measured at 405 nm from 0.1 to 0.5 m2/g. Molecular characterization further supports this darkening trend, manifesting as a depletion of small oxygenated, less absorbing monoaromatic compounds and the retention of relatively large, less polar, more absorbing constituents. Noteworthy alterations of the PO1 to PO3 mixtures included a reduction in the saturation vapor pressure of their components and an increase in viscosity. These changes were quantified by the mean values shifting from approximately 1.8 × 103 μg/m3 to 2.3 μg/m3 and from ∼103 Pa·s to ∼106 Pa·s, respectively. These results provide quantitative insights into the extent of BrC aerosol darkening during atmospheric aging through nonreactive evaporation. This new understanding will inform the refinement of atmospheric and chemical transport models.

Marangoni fireworks: Atomization dynamics of binary droplets on an oil pool

Surface tension gradient due to concentration and temperature differences induces Marangoni forces. The Marangoni effect has been extensively studied to understand its fundamental underlying physics and its industrial applications. This paper describes the spreading and atomization dynamics of an aqueous 2-propanol (IPA) solution on sunflower oil. The spreading and self-atomization of droplets by the Marangoni effect with the evaporation of volatile components are herein observed. With 40 wt. % IPA solution droplets on sunflower oil, firework-like behavior was demonstrated with the Marangoni effect. To better understand the interplay between the evaporation and spreading/atomization characteristics, the temperature field on the oil pool was visualized and quantified using an infrared camera. The Marangoni flow driven by the temperature gradient near the spreading front was estimated and compared with the experimental spreading velocity. The experimental spreading velocity of the liquid film was found to roughly agree with the model prediction. By the atomization of the spreading IPA solution, thousands of atomized daughter droplets were counted, and the size distribution was determined. Additionally, fingering instability at the interface of the IPA solution and sunflower oil was quantitatively discussed, and the resulting wavelength on its interface was compared with the capillary model. We hope that our demonstration stimulates further studies that will yield deeper insights into the spreading and atomization dynamics of volatile binary droplets on a liquid pool.

Photo-DSC method for liquid samples used in vat photopolymerization

The photo differential scanning calorimetry (photo-DSC) is an appropriate method to characterize photopolymers used in additive manufacturing (AM). Important process parameters such as optimal ultraviolet (UV) exposure time and reaction heat can be attained by this method. However, achieving reliable and meaningful results from photo-DSC experiments requires careful sample preparation, i.e. the selection of a suitable sample shape, sample mass and sample holder (crucible). The sample shapes drop and spread with 1.0 mg and 2.8 mg sample masses were investigated in this study. Three different times from sample preparation until the start of the measurement (0, 4 and 7 h) were tested, in order to investigate different surface effects such as oxygen-diffusion, prior UV-curing through ambient radiation and evaporation of volatile components. While the 1.0 mg spread sample shape offers the thinnest film thickness (40 μm) and thus the closest comparability to high resolution print jobs, the 2.8 mg drop shape offers a more robust sample preparation with minimized surface effects. To further reduce time-dependent surface effects, this study shows how a preexisting test protocol was shortened from 42 min to 24 min without losing measuring accuracy. Furthermore, to reduce evaporation, different covers were placed on different crucibles, which were tested over time in the device’s automated sample changer (ASC) that enables automated and consecutive measurements. The combination of a cold pressed 85 μL crucible covered with a 300 μL Al2O3 crucible, which is removed shortly before the actual measurement, provides the best sample preparation for the ASC since mass loss remains below 1% for up to 10 h. Finally, two two-part resin systems, namely a methacrylate-urethane and an acrylate-epoxy based resin that are used in Digital Light Synthesis (DLS) are characterized part by part as well as in mixed state. Together with the investigation of different temperatures and atmospheres, it was possible to identify not only the part with the photoinitiator and the type of system (radical or cationic), but also a difference between methacrylates and acrylates with the aid of the photo-DSC method.

Aging of bitumen on the surface of crushed granite at high temperatures

When exposed to high temperatures, bituminous materials including mixtures of crushed stone and bitumen (black gravel) quickly change their physical and mechanical properties. In the process of heating up, the structure and composition of the bitumen binding agent go through complex transformations due to the processes of polymerization, polymerization of carbons, evaporation of volatile components, etc. These processes depend on the thickness of bitumen films on the surfaces of mineral particles, depending on the type and size of mineral particles, exposure to air, magnitude and intensity of the process, high temperatures and other factors. Since bitunomineral mixtures contain mineral particles that can vary in size hundreds of times, films of different thickness and directivity are formed on their surfaces in the process of mixing with bitumen. This raises the need for a differential study of their behavior at high temperatures and changes in their adhesive properties in particular. At this, due to the lack of a standard methodology for analysis of these processes, a special estimating experimental method has been developed (see the Patent of the Russian Federation for the invention No. 2654954 [22]). The aging of the bitumen binding agent on the surfaces of mineral materials was analysed using a dimensionless aging factor for local indicators of physical and mechanical properties. According to the research based on this method, the most sensitive indicator is the compressive strenght limit at 50 degrees Celsius for standard cylindrical samples, formed from bituminous mixtures pre-heated at high temperatures. The aging of crushed granite mixtures of fr. 5…10 mm with petroleum road bitumen 90/130 was calculated at various ratios – 1:25; 1:30; 1:35; 1:40, pre-aged at + 150 °C. The aging dynamics was assesed by the values of aging intensity according to the aging coefficient. Due to the experiments, the optimum ratio of bitumen and mineral part (crushed granite) with the best resistance to aging at high temperatures and the dynamics of changing the aging intensity at different time intervals was determined. The results also include mathematical models describing the aging of mixtures under study, analysis of the experimental results and conclusions.

The role of vehicle metamorphosis on triamcinolone acetonide delivery to the skin from microemulsions.

After application to the skin surface, a topical formulation is submitted to changes in composition produced by evaporation of volatile components, penetration of components into the skin and extraction of skin components ("vehicle metamorphosis"). The aim of this work was to study the effect of vehicle metamorphosis on skin delivery from microemulsions containing triamcinolone acetonide. The microemulsions were prepared and characterized for water evaporation kinetics, in vitro release and skin permeation and retention. Skin retention experiments were performed on full thickness pig ear skin, in both occluded infinite and un-occluded finite dose conditions. For comparison purposes, two creams, the commercial Ledercort® and a vanishing cream, were tested. With triamcinolone acetonide water evaporation does not modify skin retention, probably for the lipophilic nature of the drug. However, if water is eliminated from the microemulsions, the performance is reduced, probably because drug partitioning from vehicle to stratum corneum is disfavored. If a water-soluble drug (methyl prednisolone sodium succinate) is used, infinite dose application in occlusive conditions increases in a significant way the amount of drug retained in the skin. The involved mechanisms are probably stratum corneum swelling and increase of stratum corneum/viable epidermis partitioning.

Effects of minerals on steam distillation during thermal heavy-oil recovery: An experimental investigation

ABSTRACTAn experimental study was carried out to investigate the role of various clay and non-clay minerals present in reservoir formations on steam distillation process. Dead oil samples (100 g) of two heavy oil reservoirs with 30 g of water and 10 g of crushed rock mixed with different clay minerals were kept under steam pressure with 150, 200, and 250°C in a batch autoclave reactor for a period of 40 hours, and the results were compared with respect to the changes in the density, viscosity and chemical composition of remaining heavy oil. Three different clay minerals (bentonite, kaolinite, and sepiolite) were added to the crushed rock to observe their effects. Among these clay minerals, kaolinite had the greatest effect on steam distillation. Kaolinite has an inert surface compared to other clay minerals which can be considered as an catalytic effect to make easier the evaporation of the volatile components of heavy oil during steam distillation. On the other hand, bentonite which has a swelling property in the presence of water may not allow the entrance of oil molecules because of its low permeability has retard/decrease the evaporation of volatile components. In case of kaolinite addition, density and viscosity of remaining oil are the greatest comparing with the two other minerals added. In addition, the asphaltene content of the remaining oil after distillation increased compared to original oil sample for all added clay minerals.

Effects of nano-silica and boron carbide on the curing kinetics of resole resin

In this study, the effect of nano-silica (nano-SiO2) and boron carbide (B4C) on the curing behavior of the resole resin was evaluated using differential scanning calorimetry (DSC). For the curing behavior study, DSC analysis, carried out at different heating rates, was employed to evaluate the effect of fillers on heat generated during curing and evaporation of volatile components during the curing process. A kinetic model was suggested, and its parameters were determined. The results indicated that the existence of fillers in the resin decreased the evaporation heat of volatile components; meanwhile, the incorporation of the fumed silica increased the curing heat of the resin. Also the plot of reaction rate versus conversion showed that the curing kinetic of filled resin followed the autocatalytic mechanism because of the catalytic effects of water and hydroxyl groups on the surface of nano-silica particles. Model-plotting indicated the excellent agreement between experimental and model data.

Direct measurements of the optical cross sections and refractive indices of individual volatile and hygroscopic aerosol particles.

We present measurements of the evolving extinction cross sections of individual aerosol particles (spanning 700-2500 nm in radius) during the evaporation of volatile components or hygroscopic growth using a combination of a single particle trap formed from a Bessel light beam and cavity ring-down spectroscopy. For single component organic aerosol droplets of 1,2,6-hexanetriol, polyethylene glycol 400, and glycerol, the slow evaporation of the organic component (over time scales of 1000 to 10,000 s) leads to a time-varying size and extinction cross section that can be used to estimate the refractive index of the droplet. Measurements on binary aqueous-inorganic aerosol droplets containing one of the inorganic solutes ammonium bisulfate, ammonium sulfate, sodium nitrate, or sodium chloride (over time scales of 1000 to 15,000 s) under conditions of changing relative humidity show that extinction cross-section measurements are consistent with expectations from accepted models for the variation in droplet refractive index with hygroscopic growth. In addition, we use these systems to establish an experimental protocol for future single particle extinction measurements. The advantages of mapping out the evolving light extinction cross-section of an individual particle over extended time frames accompanied by hygroscopic cycling or component evaporation are discussed.

Experimental Study of Steel Smelting Dust Component Evaporation

Evaporation of steel smelting dust components with a different content of reducing agent within it is studied by experiment. Evaporation takes place in the workspace of a tubular furnace in an inert gas stream with material density in the container of 1 g/cm3 in the temperature range 650–1200°C. The grain size composition of the original dust is studied. The elemental and phase composition of specimens (original steel smelting dust and after tests) is determined by means of an x-ray phase analyzer. The period of the end of evaporation is determined. Conditions are established for evaporation of volatile components, and the degree of metal removal is determined. Results obtained agree with those of thermodynamic calculations for reaction of components of steel smelting dust with carbon.

Evolution of a droplet medium in a plasma-chemical reactor

We modeled the plasma-chemical method of obtaining finely disperse powders by thermochemical decomposition of liquid pulverized reagents in a high-temperature heat-transfer agent in a column-type direct-flow cylindrical reactor. We consider the processes of working body motion in the reactor cavity and of thermochemical decomposition of the original solution droplets, evaporation of volatile components, and of the formation of a solid residue. The simulation of gas dynamics was made using the Reynolds equations; turbulent stresses were determined with the aid of the k–e model. In describing the formation of the solid residue, we took into account the processes of heating and evaporation of droplets, diffusion, crystallization, and of salt thermolysis in the formation of the needed structure of particles. An analysis of the results of numerical simulation of various operating conditions of the reactor is performed.

Analysis of the Phase Changes During Evaporation of Emulsions with Different Oil Phases

Emulsions surfer alterations in their microstructure after applied on the skin, because of the interaction with skin constituents and mainly by the evaporation of volatile components. These alterations are not even considered by cosmetic formulators, but they are extremely important because they can act on formulation stability, on delivery and on permeation of actives and also on the ability to build the occlusive film, responsible for skin's moisturization. This research studied the phase changing during evaporation of emulsions made with three different oil phase: mineral oil, avocado oil, and isocethyl/stearoil stearate, as a function of the decrease on water ratio, using phase diagrams and evaporation test. It was observed the formation of liquid crystalline phases and their transition along the evaporation path for emulsions with the three different oil phases. It was also observed that these transitions occurred in different water ratios.

Influence of additional thermal stabilizers on the reprocessing of postconsumer poly(vinyl chloride) bottles

AbstractThe addition of heat stabilizers is essential for preventing the degradation of poly(vinyl chloride) (PVC) during its processing. The heat stabilizers consumed in the first run have to be made up before the reprocessing of recycled PVC. In this study, solvent‐cast films, which were prepared from granulated postconsumer PVC bottles mixed with plasticizers and thermal stabilizers, were used. The films were subjected to various heat treatments. No considerable structural change upon heat treatments at 140–160°C was found in IR and differential scanning calorimetry analyses. Polyene formation observed through ultraviolet analysis was not severe, indicating that the added stabilizers worked well in preventing degradation. The weight loss during the heat treatments was attributed partly to the decomposition of PVC and the evaporation of volatile components and mainly to the removal of the solvent upon heating. Although this study was conducted with water bottles that were to be recycled, it may be equally well applied to other similarly formulated PVC‐based materials, such as packaging films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3994–3999, 2003

Effect of evaporation and mixing technique on die spacer thickness: A preliminary study

Statement of problem. Casting relief is required for proper seating of castings to allow for luting agent thickness. The application of die spacer to the die is the most common method of obtaining casting relief. Die spacer film thicknesses that are outside the ideal range of 25 to 40 μm can cause clinical problems. Thickness can be affected by the separation of die spacer constituents, which may not be reconstituted by mixing, in the bottle and by the evaporation of volatile components while the bottle is open.Purpose. The purpose of this study was to determine the effects of component evaporation and die spacer mixing technique on applied die spacer thickness.Material and methods. Bottles of Gold Tru-fit die spacer were left open for 0, 1, 4, 8, and 24 hours at 22°C. Spacer solutions were shaken either by hand per the manufacturer's directions or on a dental vibrator for 1 minute. One even brush stroke of spacer was applied to clean glass slides. Three die spacer films were made for each combination of time and mixing technique. Eighteen thickness measurements per sample at various sites were recorded with profilometer tracings. Statistical differences were determined with a 2-way ANOVA.Results. Handshaking provided greater die spacer thickness, which increased with the time that the bottle was open. Vibration provided lower thickness with no statistical increase with time.Conclusion. Insufficient agitation caused lower film thickness. Excessive evaporation caused higher film thickness. (J Prosthet Dent 2001;85:82-7.)

Liquid-phase sintering of PZT ceramics

Lead zirconate titanate (abbreviated as PZT) ceramics are of considerable commercial importance for a host of piezoelectric and pyroelectric applications. Conventionally, many PZT ceramics are sintered at temperatures above 1250°C. Such extreme temperatures are undesirable due to the increased energy consumption, limitation of electrode material and evaporation of volatile components. A liquid-phase sintering aid incorporating Cu 2O and PbO is presented which demonstrates a reduction in the required sintering temperature of these ceramics. This new aid is described with particular reference to a commercial PZT, termed Pz26, used industrially for its optimised piezoelectric properties. Pz26 has a composition near the morphotropic phase boundary and possesses a tetragonal crystalline structure. Typically this material is sintered between 1260 and 1300°C for 1 h to achieve the required densification. With the inclusion of sintering aid, sintered densities comparable to those obtained by conventional sintering are achieved at only 800°C. The optimum weight percentage of sintering aid varies for different ceramic materials, particle sizes, morphology and the desired sintering temperature. However, with standard “mixed-oxide” produced Pz26 powder and with a median particle size in the range 1.6–1.7 μm, a value of 5 wt.% allows sintering at 800°C, according to densification, dielectric and piezoelectric measurements ( ϵ=873, tan δ=1.13 %, k p=43.1%). When finer grained powder is used ( d 0.5=1.1 μm), improved properties ( ϵ=960, tan δ=1.04%, k p=51.7%) are obtained for an addition of 3 wt.% sintering aid and a sintering temperature of 850°C.

Evaporation of volatile component from lamina of solution in the presence of a gravitational field

A kinetic model of the process of volatile component evaporation from a solution in the presence of a gravitational field has been elaborated. The evaporation is supposed to occur into an indifferent gas stream, flowing above the upper surface of a thin flat layer of the solution. The model is based on a one-dimensional diffusion equation in an external field. The cases of evaporation of both atoms and diatomic molecules of the volatile component from the atomic solution in a non-volatile solvent were considered. The analysis of the expressions of evaporation rate and volatile component concentration in the liquid phase as functions of time and parameters of the system has been carried out as well.

The leveling of thermosetting waterborne coatings. Part IV: Effects of film thickness

AbstractThe influence of film thickness on the leveling of a thermosetting waterborne coating (WBC) was examined. The theory of Patton has been revised to give the proper force balance and modified to include the changes in surface tension and viscosity during leveling by the evaporation of volatile components. However, the predicted leveling process by a numerical method did not coincide with the observed results. Thus, the driving force in the theory, the hydrostatic pressure gradient in the film, was considered to be insufficient to describe the leveling process of the WBC. The hydrostatic pressure gradient can be a component of the driving force to promote leveling, but the existence of an additional component is suggested.

Evolution of gases from refractory mixtures on the btso phenol-furfural binder

Using the BTSO phenol-furfural binder as an example, the main regularities of the evolution of volatile phenolic resins from refractory mixtures are considered. The evolution of gases is treated as being a result of two competitive processes, namely, the evaporation of volatile components and their combination into a solid or gel-like phase.

Oxyhydrogen burner for low-temperature flame fusion

An oxyhydrogen burner as described in this article enables the growth of crystals by Verneuil’s technique at temperatures of about 1000 °C. The powder fed to the crystal passes along a low-temperature pathway through the flame, so that evaporation of volatile components is prevented. Low-temperature flame fusion of superconducting Y-Ba-cuprate is reported.

Pulsed excimer laser deposition of ferroelectric thin films

Abstract Pulsed UV excimer laser ablation was employed to deposit multi-axial, bi-axial and uni-axial ferroelectric compositions of PZT, bismuth titanate and lead germanate respectively. In general, a fluence lower than 2 J/cm2 caused a preferential evaporation of volatile components, resulting in stoichiometric imbalance. However, the fluences beyond 2 J/cm2 enabled the deposition of stoichiometric thin films of multi-component oxide systems. The intrinsic bombardment due to the energetic ablated species during the thin film deposition seemed to influence the composition, structure, orientation and the electrical properties. The electrical characterization of ferroelectric films indicated a dielectric constant of 800–1000, a Pr of 32μC/cm2 and Ec of 130KV/cm for polycrystalline PZT films and the corresponding quantities were measured to be 150, 7 μC/cm2 and 20 KV/cm for in-situ crystallized c-axis preferred oriented bismuth titanate films. Lead germanate thin films oriented along c-axis (003) showed a di...

Hydrogenation Mechanism of Coal Tar Pitch for Carbon Fiber(Part 3). Effects of Hydrotreatment on Pyrolysis Reactivity of Each Component in Coal Tar Pitch for High Performance Carbon Fiber.

Coal tar pitch for high performance carbon fiber (HPCF) was hydrotreated using tritium labelled tetralin as donor solvent at 450°C for 120min. The hydrogen transfer in this process was determined quantitatively according to results obtained from radioisotope tracer method. The hydrotreatment of pitches can be explained by a general mechanism such as involved in the hydrotreatment of petroleum heavy oil or coal liquefaction. The tritiated pitch was heat-treated in the range of 30 to 1, 000°C under nitrogen atmosphere. It was found that the reaction of carbon-carbon bond cleavage and the evaporation of volatile components were basically completed at about 600°C. The dehydrogenation of polynuclear aromatic rings was sustained up to 1, 000°C. The model based on the first order rate expression was able to analyse TGA data successfully. Activation energies and frequency factors, for the nonisothermal heat treatment of pitches and each component of pitches, were calculated. The pyrolysis activation energies of the pitch and major components (HIS-BS and BIS-THFS fractions) in the pitch decreased when the pitch was hydrotreated.