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Secondary organic aerosols (SOA) constitute an important fraction of fine-mode atmospheric aerosol mass. Frameworks used to develop SOA parameters from laboratory experiments and subsequently used to simulate SOA formation in atmospheric models make many simplifying assumptions about the processes that lead to SOA formation in the interest of computational efficiency. These assumptions can limit the ability of the model to predict the mass, composition, and properties of SOA accurately. In this work, we developed a computationally efficient, process-level model named simpleSOM to represent the chemistry, thermodynamic properties, and microphysics of SOA. simpleSOM simulates multigenerational gas-phase chemistry, phase-state-influenced kinetic gas/particle partitioning, heterogeneous chemistry, oligomerization reactions, and vapor losses to the walls of Teflon chambers. As a case study, we used simpleSOM to simulate SOA formation from the photooxidation of α-pinene. This was done to demonstrate the ability of the model to develop parameters that can reproduce environmental chamber data, to highlight the chemical and microphysical processes within simpleSOM, and discuss implications for SOA formation in chambers and in the real atmosphere. SOA parameters developed from experiments performed in the chamber at the California Institute of Technology (Caltech) reproduced observations of SOA mass yield, O : C, and volatility distribution gathered from other experiments. Sensitivity simulations suggested that multigenerational gas-phase aging contributed to nearly half of all SOA and that in the absence of vapor wall losses, SOA production in the Caltech chamber could be nearly 50% higher. Heterogeneous chemistry did not seem to affect SOA formation over the short timescales for oxidation experienced in the chamber experiments. Simulations performed under atmospherically relevant conditions indicated that the SOA mass yields were sensitive to whether and how oligomerization reactions and the particle phase state were represented in the chamber experiment from which the parameters were developed. simpleSOM provides a comprehensive, process-based framework to consistently model the SOA formation and evolution in box and 3D models.

Organic aerosol constitutes a major fraction of the global aerosol burden and is predominantly formed as secondary organic aerosol (SOA). Environmental chambers have been used extensively to study aerosol formation and evolution under controlled conditions similar to the atmosphere, but quantitative prediction of the outcome of these experiments is generally not achieved, which signifies our lack in understanding of these results and limits their portability to large-scale models. In general, kinetic models employing state-of-the-art explicit chemical mechanisms fail to describe the mass concentration and composition of SOA obtained from chamber experiments. Specifically, chemical reactions including the nitrate radical (NO3) are a source of major uncertainty for assessing the chemical and physical properties of oxidation products. Here, we introduce a kinetic model that treats gas-phase chemistry, gas–particle partitioning, particle-phase oligomerization, and chamber vapor wall loss and use it to describe the oxidation of the monoterpenes α-pinene and limonene with NO3. The model can reproduce aerosol mass and nitration degrees in experiments using either pure precursors or their mixtures and infers volatility distributions of products, branching ratios of reactive intermediates and particle-phase reaction rates. The gas-phase chemistry in the model is based on the Master Chemical Mechanism (MCM) but trades speciation of single compounds for the overall ability of quantitatively describing SOA formation by using a lumped chemical mechanism. The complex branching into a multitude of individual products in MCM is replaced in this model with product volatility distributions and detailed peroxy (RO2) and alkoxy (RO) radical chemistry as well as amended by a particle-phase oligomerization scheme. The kinetic parameters obtained in this study are constrained by a set of SOA formation and evaporation experiments conducted in the Georgia Tech Environmental Chamber (GTEC) facility. For both precursors, we present volatility distributions of nitrated and non-nitrated reaction products that are obtained by fitting the kinetic model systematically to the experimental data using a global optimization method, the Monte Carlo genetic algorithm (MCGA). The results presented here provide new mechanistic insight into the processes leading to formation and evaporation of SOA. Most notably, the model suggests that the observed slow evaporation of SOA could be due to reversible oligomerization reactions in the particle phase. However, the observed non-linear behavior of precursor mixtures points towards a complex interplay of reversible oligomerization and kinetic limitations of mass transport in the particle phase, which is explored in a model sensitivity study. The methodologies described in this work provide a basis for quantitative analysis of multi-source data from environmental chamber experiments but also show that a large data pool is needed to fully resolve uncertainties in model parameters.

Highly concentrated electrolytes exhibit advantages in enhanced stability, low solvent volatility, and superior battery safety. It is therefore important to design salts that push the limit of solu...

Oxy-fuel combustion of heavy oil can be applied to oil field steam injection boilers, allowing the utilization of both heavy oil and CO2 resources. This paper studied the local distribution characteristics of OH on oxy-fuel combustion of heavy oil during the ignition and stable combustion processes. During the ignition process, we observed the generation and evolution of fire kernel, and got the flame propagation velocity. During the stable combustion process, the results showed that the OH distribution and its relative signal intensity were influenced by the oxygen concentration, excess air coefficient, gas flow, reaction atmosphere, oil mist scattering, incident laser energy and laser sheet position. In the same reaction atmosphere, the ranges of OH dense distribution and the high temperature area increased as O2 concentration increased. In the same O2 concentration, both the ranges of OH dense distribution and the high temperature area in O2/N2 were larger than that in O2/CO2. In 29% O2/71% CO2, the flame shape was similar to combust in air, while the OH relative signal intensity and its volatility were much larger than that in air. In the same combustion condition, the location of high concentration of OH relative concentration field lagged behind the high temperature area. The results further reveal the differences between the conventional and oxy-fuel combustion.

Supported catalysts were prepared with CeCl3 and CeO2 as active components, the catalytic degradation of volatiles from pine particle pyrolysis was studied. Activated alumina was used as the carrier of CeO2 and CeCl3 to prepare CeO2/Al2O3 and CeCl3/Al2O3 catalysts. Experimental results show that the two catalysts can effectively reduce the yield of pyrolysis liquid-phase products and markedly increase the yield of gas-phase products. Compared with no catalyst, the liquid product yield decreased by 25.69% and the pyrolysis gas yield increased by 29.48% at a pyrolysis temperature of 650 °C by using CeO2/Al2O3 catalyst. The active components in CeO2 reduced the volume fraction of CnHm in pyrolysis gas and increased the volume fraction of H2. Under the catalysis of CeCl3/Al2O3, the CO content and the low calorific value of the product gas increases. The addition of the two catalysts cracked the oxygen-containing functional groups in the tar to various extents, reducing the tar yield and increasing the pyrolysis gas yield. For the simple reduction of tar yield in pyrolysis gas, the catalytic cracking effect of CeO2/Al2O3 catalyst was better than that of CeCl3/Al2O3 catalyst, and CeCl3/Al2O3 catalyst should be selected when degrading tar while obtaining a relatively high low heating value.

The use of Fischer-Tropsch (F-T) diesel synthesized from coal in automobiles can alleviate the shortage of petroleum and promote clean utilization of coal. In this study, the effects of injection timing (IT) and rail pressure (RP) on the brake thermal efficiency (BTE), combustion characteristics, and cyclic variations of F-T diesel were investigated on a turbocharged, 6-cylinder, common rail direct injection (CRDI) diesel engine. The results indicate that increasing RP results in higher BTE, whereas advancing IT results in an initial BTE increase and a subsequent BTE decrease. In comparison with petroleum diesel, the BTE of F-T diesel increased by 0.54% on average and by a maximum of 1% under different conditions. When the IT was advanced from 2 °CA to 18 °CA BTDC, the ignition delay periods (IDP) first decreased and then increased, whereas the combustion durations (CD) first lengthened and then shortened; peak cylinder pressure (PCP), peak pressure rise rate (PPRR), and peak combustion temperature (PCT) gradually increased; peak heat release rate (PHRR) first decreased and then increased at the low loads, whereas it always increased at medium and high loads. In comparison with petroleum diesel, the IDP of F-T diesel decreased by 22–31% at various conditions, and the CD was slightly longer than that of petroleum diesel at most conditions. Additionally, increasing RP resulted in a decrease in the IDP and CD, and a significant increase in PCP, PPRR, PHRR, and PCT. At low loads, the PPRR and PHRR of F-T diesel were 32.72% and 32.13% lower than that of diesel owing to the shorter ignition delay. This implies that using F-T diesel can help in attaining smoother engine running and has lower combustion noise. Advancing the injection timing or increasing the engine loads can decrease the cyclic variations, whereas increasing rail pressure results in the increment of COVpmax at low loads and the significant decrement of COVpmax at medium and high loads. In comparison with petroleum diesel, F-T diesel exhibits higher combustion stability owing to the better volatility and higher fuel reactivity.

Background Although the structure and physicochemical properties of large ring cyclodextrins (LR-CDs) exhibit unique characteristics, and also possess very strong water solubility and high safety, little is known about the embedding performance of macrocyclodextrin. Encapsulation refers to a complex of tea tree oil (TTO) with the wall material, protecting the core material or changing its properties from adverse external factors, controlling its release rate against the evaporation and degradation of essential oils. In the present study, LR-CDs complexed with TTO were prepared by co-precipitation methods. Results The mass ratio of LR-CDs-TTO was six and the maximum complexation efficiency was 86.23%. Fourier-transform infrared spectroscopy analysis presented the loss of characteristic peaks related to TTO in the complex and no other additional peaks were observed. X-ray diffraction examination demonstrated several sharp peaks and intensity peaks at the diffraction angle of the TTO-LR-CDs complex. 1 H-NMR indicated a chemical shift as a result of the interaction between the molecules in the inclusion complex. Moreover, the thermal stability and aqueous solubility of TTO were enhanced after synergy with LR-CDs; particularly, the solubility of the complex was increased by 329-fold. The volatile characteristics of the encapsulated and original TTO were identical. Conclusion The results of the present study show that TTO was efficaciously complexed with LR-CDs and exhibited enhanced solubility and thermal stability. © 2020 Society of Chemical Industry.

Trimethylamine (TMA) is ubiquitous in the marine systems and may affect atmospheric chemistry as a precursor and strong stabilizer of atmospheric secondary aerosol, influencing cloud formation. Rapid and accurate measurement of the concentration of TMA in seawater is challenging due to their polarity, aqueous solubility, volatility and existence at low concentrations in marine environments. In this study, a dopant-assisted atmospheric pressure photoionization time-of-flight mass spectrometry (DA-APPI-TOFMS) coupled with a dynamic purge-release method was developed for rapid and sensitive analysis of TMA in seawater. A novel three-zones ionization source has been developed for improving the ionization efficiency of analyte molecules and minimizing the influence of high-humidity of the sample gas, which allowed direct analysis of high-humidity (RH> 90%) gas samples from microbubble purging process by the mass spectrometer. At atmospheric pressure, the three-zones ionization source allows the use of high-speed purge gas to quickly purge all organic amines dissolved in the water into the gas phase, ensuring quantitative accuracy. The limit of quantification (LOQ) for TMA down to 0.1 μg L−1 was obtained in less than 2 min by consuming only 2 mL seawater sample. This method was applied for the determination of the concentrations of TMA in the coastal seawater to validate its practicability and reliability for analysis of trace amines in marine environments.

The development of sensitive fluorescence sensors and efficient preparation of samples is a challenge in the detection of pesticides in complex samples. In this study, multicolor nitrogen dots (M-Ndots) were synthesised via microwave irradiation at 140 °C for 10 min with 5-amino-1H-tetrazole and p-phenylenediamine as precursors, which have a high fluorescence quantum yield of up to 31%. Furthermore, the M-Ndots were employed as fluorescence sensors for pesticide detection by being combined with a gas membrane separation device, to eliminate the interference from the complex sample matrix. In this process, the M-Ndots were used for sensing thiram and chlorpyrifos through their affinities to Cu2+ and Fe3+, respectively. Because thiram could decompose into volatile CS2, its derivate was sensed using the fluorescence of M-Ndots via a complexation reaction with Cu2+. Chlorpyrifos, due to its volatility, can reduce the Fe3+ ion by inhibiting the activity of acetylcholinesterase, which produces H2O2 to oxidise Fe2+. In a real application, the time consumption for 96 samples was less than 30 min in one run of the gas membrane separation device. The recoveries for thiram and chlorpyrifos ranged from 90.0% to 115.0%, and the analytical results were validated using LC-MS/MS methods, with relative errors ranging from −7.4% to 10.1%.

Intermediate volatility and semivolatile organic compounds (IVOC/SVOC) are important precursors of secondary organic aerosol (SOA) while SVOC is an important contributor to primary organic aerosol (POA). However, combustion emissions data for volatility classes are limited. This study reports the gas and particle emissions that were sampled with various dilution factors from a sewage sludge incinerator burning fuel oil. Volatility distributions were determined using measurements from online mass spectrometry and offline organic compound analyses. In the low volatility organic compound (LVOC) to IVOC range, volatility bins with organic saturation concentrations of 10-100 μg m-3 were most abundant, which was due to organic acids generated from sludge burning. Organic aerosol (OA) emission factors (EFOA) increased 1.4 times after cooling to ambient temperatures in comparison to those of the samples from the hot stack. Upon further isothermal dilution at 25 °C, the EFOA decreased while organic gas phase EFs increased with increasing dilution. Phase partitioning in volatility bins with saturation concentrations of 10-100 μg m-3 was sensitive to isothermal dilution that influenced the EFs. Therefore, gas- and particle-phase measurements alone cannot constrain EFs for these volatility classes. Low dilution factors may overestimate the particle phase and underestimate the gas phase EFs compared with real-world emission conditions.

The plant cuticle is the final barrier for volatile organic compounds (VOCs) to cross for release to the atmosphere, yet its role in the emission process is poorly understood. Here, using a combination of reverse-genetic and chemical approaches, we demonstrate that the cuticle imposes substantial resistance to VOC mass transfer, acting as a sink/concentrator for VOCs and hence protecting cells from the potentially toxic internal accumulation of these hydrophobic compounds. Reduction in cuticle thickness has differential effects on individual VOCs depending on their volatility, and leads to their internal cellular redistribution, a shift in mass transfer resistance sources and altered VOC synthesis. These results reveal that the cuticle is not simply a passive diffusion barrier for VOCs to cross, but plays the aforementioned complex roles in the emission process as an integral member of the overall VOC network.

The fossil fuel energy sources over the world are depleting day by day. In this situation, there is a necessity to explore for substitute fuels. Low volatility, filter clogging and high viscosity a...

As a step toward licensing a lead–bismuth eutectic (LBE) based reactor design, the adsorption behavior of iodine evaporated from LBE on fused silica was examined. Using inert and reducing carrier gases, depositions with an adsorption enthalpy of − 95 to − 113 kJ mol−1 were observed. These depositions are compatible with a single species, tentatively identified as bismuth monoiodide, BiI. When introducing oxidizing conditions, multiple iodine species with higher volatility form, with adsorption enthalpies ranging from − 67 to − 86 kJ mol−1. Based on an empirical correlation one of these species was identified as monatomic iodine. This work provides fundamental understanding of the LBE/iodine gaseous chemistry and related adsorption deposition behavior.

Mercury in flue gas has been identified to be one of the most harmful environmental pollutants to humans and other organisms as a result of its bioaccumulation, volatility, persistence, high toxici...

Ifosfamide (IF), cyclophosphamide (CP), and bendamustine (BD) are widely used anticancer drugs. These drugs have slight volatility; therefore, medical-staff exposure is of concern in the medical field. However, an accurate and quantitative detection method of these volatile drugs in air has not been reported. In this study, we developed the quantitative extraction and detection method of these volatile anticancer drugs in air. For the extraction of analytes, a solid-phase extraction-type collection device packed with styrene-divinylbenzene polymer particles was used. The extracted analytes were quantitatively eluted with 5 mL of ethanol, and the solution was concentrated to 100 μL with nitrogen purging. The analytes were analyzed using gas chromatography-mass spectrometry (GC-MS). The limit of detection of the proposed method for IF and CP was 0.017 and 0.033 ng L-1, respectively in air at an air sampling volume of 300 L. IF and CP showed slight volatility, whereas BD was not detected in GC-MS due to its lower volatility. The spiked recoveries of IF and CP in the proposed method were within the range of 95.5 to 101%. Finally, the proposed method was applied to determine the exposure of IF and CP during the dispensing of CP within a hospital dispensary room. The investigated volatile anticancer drugs were not detected in real air samples, indicating that the protection measures employed are sufficient.

This paper focuses on the electrical properties and stability against DC accelerated aging stress of ZnO-V2O5-MnO2- Nb2O5-Bi2O3-Co3O4-Dy2O3 (ZVMNBCD) varistor ceramics sintered at 850 - 925 ℃. With the increase of sintering temperature, the average grain size increases from 4.4 to 11.8 mm, and the density of the sintered pellets decreases from 5.53 to 5.40 g/ cm3 due to the volatility of V2O5, which has a low melting point. The breakdown field abruptly decreases from 8016 to 1,715 V/cm with the increase of the sintering temperature. The maximum non-ohmic coefficient (59) is obtained when the sample is sintered at 875 ℃. The samples sintered at below 900 oC exhibit a relatively low leakage current, less than 60 mA/cm2. The apparent dielectric constant increases due to the increase of the average grain size with the increase of the sintering temperature. The change tendency of dissipation factor at 1 kHz according to the sintering temperature coincides with the tendency of the leakage current. In terms of stability, the samples sintered at 900 ℃ exhibit both high non-ohmic coefficient (45) and excellent stability, 0.8% in ΔEB/EB and -0.7% in Δα/α after application of DC accelerated aging stress (0.85 EB/85 oC/24 h).

Mg3Sb2-based materials possess promising thermoelectric performances, however, probably poor interfacial behaviors when connected with the metal electrodes due to the strong chemical activity and volatility of the element Mg. In this paper, a high conversion efficiency of up to 9 % was achieved with a reliable Mg3.2Sb1.5Bi0.49Te0.01/304 stainless steel junction at a temperature difference of 370 K (Th = 673 K, Tc = 303 K). The transformation from a single ferritic structure (Fe) to an austenitic structure (304 stainless steel) insures the lower diffusion coefficient and higher expansion coefficient of 304 stainless steel, which contributes to the suppressed interfacial reaction, ideal electrical properties, and robust mechanical properties from room temperature to higher temperature.

The effect of different rare-earth oxides additives (La2O3, Nd2O3, Y2O3, Sm2O3, Yb2O3 and Lu2O3) on the stability of SiO2 glass at 1973 K was systematically studied employing volatility test and first-principles calculations. Both experimental and theoretical results show that the introduction of rare-earth oxides plays an active role in developing the stability of SiO2 glass at 1973 K due to the presence of Re2Si2O7 (Re= La, Nd, Y, Sm, Yb, Lu) phase. SiO2 glass samples doped with rare-earth oxide owning smaller cationic radius show better stability at 1973 K. Re atoms in Re2Si2O7 can diffuse into SiO2, which tends to occupy the interstitial site of SiO2 network. The influence of various interstitial Re atoms on SiO2 network are different and the inLu-SiO2 structure is the most stable. Meanwhile, the diffusion of Re atoms enhances the interface bonding between SiO2 (0 1 0) and inRe-SiO2 (1 1 2) and the inLu-SiO2 (1 1 2)/SiO2 (0 1 0) interface owns the highest binding energy, which is profitable to develop the thermal stability of SiO2 glass at 1973 K.

The influence of bioethanol content and parameters of the cavitation field on the quality indicators of motor gasolines: volatility and octane number is studied. Studying the effect of bioethanol and cavitation treatment of bioethanol-gasoline mixture will make it possible to produce automotive fuels for different climatic zones, or winter (summer) versions of gasolines. The use of bioethanol and cavitation treatment of a bioethanol-gasoline mixture affect the fractional composition of motor gasoline and its volatility. The optimal content of the biocomponent, at which there is an increase in the volatility of gasoline, is established Also the results of the octane number change are presented depending on the intensity of cavitation treatment for gas condensate with the addition of bioethanol. The influence of bioethanol content on the increase in octane number during cavitation treatment is determined. It is found that the introduction of bioethanol into the composition of gasoline leads to an improvement in its volatility. In this case, cavitation treatment makes it possible to obtain a mixture resistant to delamination. The addition of bioethanol leads to an adequate increase in light fractions during mechanical mixing and to a change in the fractional composition of the bioethanol-gasoline mixture during cavitation treatment. The addition of bioethanol in amounts up to 10% leads to a decrease in the saturated vapor pressure during cavitation treatment of bioethanol-gasoline mixtures, and an increase in the bioethanol content up to 20% leads to an increase in the saturated vapor pressure, which is explained by a change in the chemical composition of fuel components in comparison with the mechanical method of preparing mixtures. By cavitation treatment it is possible to change the fractional composition, the pressure of saturated vapors and the volatility of bioethanol-gasoline mixtures, making cavitation a promising energy-saving process for the production of gasoline for various climatic conditions

In this study, four isomerate-enriched gasolines were formulated from the local refinery streams of Cairo Petroleum Refinery Co., Egypt. Each of these isomerate-enriched hydrocarbon gasolines were mixed with 10 vol% of anhydrous ethanol. Distillation data were collected for the eight formulated fuels using the standard ASTM-D86 distillation method. From these data, eight distillation profiles were constructed and subsequently eight distillation profiles equations, were developed. From these equations, areas under distillation curves for the hydrocarbon gasolines (AUDC)G and those for ethanol blended ones (AUDC)G-10E were estimated using calculus definite integration method. Accordingly, area due to azeotrope formation (ADAF) for each ethanol-blended fuel was calculated (AUDCG-AUDCG-10E). Also, vapor pressure, T(v/l) = 20, T50 and deriveability index (DI) of the fuel samples were studied. The results confirm that the volatility of all fuel formulations considerably increases with addition of 10 vol% ethanol while it slightly increases with the slight increase in the isomerate content.

Deep eutectic solvents (DESs) have widely applied in various fields. Given this and that DESs has low toxicity and are green solvents, new aspects of these solvents have been recently considered by researchers. In this review, after a brief explanation of different types and the physicochemical properties of DESs, i.e., melting temperature, volatility, viscosity, electric conductivity; their applications in extraction of various compounds e.g. organic and inorganic chemicals, pharmaceuticals, pesticides and proteins, biodiesel production, pharmaceutical applications, catalyst and gas capture were presented so that researchers can find out about the new aspects of these solvents.

Creation of geological and simulation models is the necessary condition for decision making towards current development status, planning of well interventions, field development planning and forecasting. In case of isothermal process, for proper phase behavior and phase transitions two key approaches are used: a) simplified model of non-volatile oil, so called “black oil” model, in which each phase – oil, water and gas, are represented by respective component, and solution to fiow equations is based on finding the saturations and pressures in each numerical cell, and change of reservoir fiuid properties is defined in table form as a function of pressure; b) compositional model, in which based on equation of state, phase equilibrium is calculated for hydrocarbon and non-hydrocarbon components, and during fiow calculations, apart from saturations and pressures, oil and gas mixture is brought to phase equilibrium, and material balance is calculated for each component in gas and liquid phase. To account for components volatility, the classic black oil model was improved by adding to the formulation gas solubility and vaporized oil content. This allows its application for the majority of oil and gas reservoirs, which are far from critical point and in which the phase transitions are insignificant. Due to smaller number of variables, numerical solution is simpler and faster. But, considering the importance and relevance of increasing the production of Ukrainian gas and optimization of gas-condensate fields development, the issue of simplified black oil PVT-model application for phase behavior characterization of gas-condensate reservoirs produced under natural depletion depending on the liquid hydrocarbon’s potential yield. Comparative study results on evaluation of production performance of synthetic reservoir for different synthetically-generated reservoir fiuids with different С5+ potential yield is provided as plots and tables. Based on the results the limit of simplified black oil PVT-model application and the moment of transition to compositional model for more precise results could be defined.

We report on the vapor pressures at ambient temperatures of seven attractants of Bactrocera, Dacus, and Zeugodacus fruit flies—raspberry ketone, cuelure, raspberry ketone trifluoroacetate, methyl e...

Unlike the deep understanding of highly oxygenated organic molecules (HOMs) driving continental new particle formation (NPF), little is known about the organic compounds involved in coastal and open-ocean NPF. On the coastline of China we observed intense coastal NPF events initiated by iodine nucleation, but particle growth to cloud condensation nuclei (CCN) sizes was dominated by organic compounds. This article reveals a new group of C18,30HhOoNn and C20,24,28,33HhOo compounds with specific double-bond equivalents and oxygen atom numbers in new sub 20 nm coastal iodine particles by using ultrahigh-resolution Fourier transform–ion cyclotron resonance mass spectrometry (FT-ICR-MS). We proposed these compounds are oxygenated or nitrated products of long-chain unsaturated fatty acids, fatty alcohols, nonprotein amino acids or amino alcohols emitted mutually with iodine from coastal biota or biologically active sea surface. Group contribution method estimated that the addition of –ONO2, –OH and –C=O groups to the precursors reduced their volatility by 2–7 orders of magnitude and thus made their products condensable onto new iodine particles in the coastal atmosphere. Nontarget MS analysis also provided a list of 440 formulas of iodinated organic compounds in size-resolved aerosol samples during the iodine NPF days, which facilitates the understanding of unknown aerosol chemistry of iodine.

Water washing on biomass can effectively remove K, Na and Cl, which will cause serious problems such as fouling, slagging and corrosion during thermal conversion processes of biomass. But amounts of leachates remain to be disposed. Investigating the organics release will be helpful to the leachate disposal. In this study, four types of biomass are water washed at different temperatures. The organic species and DBP (di-n-butyl phthalate) concentrations in leachates are determined by GC-MS. The results show that organics tend to release in the high-temperature region (60–90 °C). At 90 °C, 80% of organic matters in the wheat straw leachate are AR (aromatic hydrocarbons) and AL (alkanes, cycloalkanes and heterocyclic hydrocarbons). The organics distributions in the rice hull leachate are relatively uniform, compared with other leachates. The DBP concentrations in four leachates at 90 °C are lower than that at 30 °C because of its volatility. DBP concentrations in rice hull and corn stalk leachates show a trend of “reduction−increase”, with minimum values of 0.0001 and 0.001 mg L−1 at 60 °C, respectively. Whereas in the sorghum stalk leachate, a tendency of “increase−reduction” is observed. The corresponding content achieves the maximum value of 0.024 mg L−1.

Single droplet levitation provides contactless access to the microphysical and chemical properties of micrometer-sized samples. Most applications of droplet levitation to chemical and biological systems use nondestructive optical techniques to probe droplet properties. To provide improved chemical specificity, we coupled a multicompartment quadrupole electrodynamic trap (QET) with single droplet mass spectrometry. Our QET continuously traps a monodisperse droplet population (tens to hundreds of droplets) and allows for the simultaneous sizing of a single droplet using its Mie scattering pattern. Single droplets are subsequently ejected into the ionization region of an ambient pressure inlet mass spectrometer. We optimized two complementary soft ionization techniques for picoliter aqueous droplets: (1) paper spray (PS) ionization and (2) thermal desorption glow discharge (TDGD) ionization. Both techniques detect oxygenated organic acids in single droplets, with signal-to-noise ratios >100 and detection limits on the order of 10 pg. Sensitivity and reproducibility across single droplets are driven by the droplet deposition location and spray stability in PS-MS and the ionization region humidity and analyte evaporation rate in TDGD-MS. Importantly, the analyte evaporation rate can control the TDGD-MS quantitative capability because high evaporation rates result in significant ion suppression. This effect is mitigated by optimizing the vaporization temperature, droplet size range, and analyte volatility. We demonstrate quantitative and reproducible measurements with a droplet internal standard (

Objectives. The conditions for the effective application of the sharp distillation technique (without a component distributed between the distillate and bottom flows) for the separation of quaternary zeotropic mixtures containing components with similar volatilities were determined. The area of energy advantage for the flowsheet based on the preliminary fractionation of the mixture, compared with the flowsheet, the first distillation column of which works based on the indirect separation mode, was identified for an ethyl acetate–benzene–toluene–butyl acetate system. Energy savings of up to 20% were achieved. The direct and indirect distillation modes can become competitive when the point of the original composition is located near single K-surfaces or in a region with a different ratio of distribution coefficients. Sharp distillation is not suitable for the separation of a mixture containing a pair of components exhibiting relative unity volatility with medium boiling points.Methods. The mathematical modeling in the Aspen Plus V.10.0 software package was chosen as the research method. The simulation was based on the Wilson local composition equation. The relative errors in the description of the phase equilibrium did not exceed 3%.Results. The structure of the vapor–liquid equilibrium diagram and diagram of surfaces of the unit component distribution coefficients were studied for the ethyl acetate–benzene–toluenebutyl acetate and acetone–toluene–butyl acetate–o-xylene systems. Flowsheets based on the sharp, indirect (both systems), or direct (second system) distillation modes were proposed. The distillation process was simulated, and the parameters of the column work were determined (the quality of the substances meets the State Standard requirements of the Russian Federation for minimal energy consumption).Conclusions. Recommendations regarding the use of sharp distillation for the separation of quaternary mixtures containing components with similar volatilities were devised.

This work focuses on zero-dimensional modeling of the heat release rate in a compression ignition engine operating on gasoline-like fuels. Due to the properties of gasoline, such as high volatility and longer ignition delay than diesel, the injection strategies can vary significantly from the operation with conventional diesel fuel. Different injection strategies are commonly used to achieve varying degrees of in-cylinder stratification in order to shape the combustion event and maximize efficiency. The proposed zero-dimensional combustion model was developed to account for the different stages in combustion caused by the fuel stratification. As the ignition delay model is an integral part of the entire combustion process and significantly affects the prediction accuracy, special attention has been paid to local phenomena influencing ignition delay. A one-dimensional spray model by Musculus and Kattke was employed in conjunction with a Lagrangian tracking approach in order to estimate the local air–fuel ratio within the spray tip, as a proxy for reactivity. The local air–fuel ratio, in-cylinder temperature and pressure were used in an integral fashion to estimate the ignition delay. Heat release rates were modeled using first-order non-linear differential equations. The proposed combustion model was validated against experimental data of a heavy-duty compression ignition engine with up to three injection events at mostly 1038 r/min and 14 bar brake mean effective pressure. Further validation of the model was carried out at other engine loads and speeds. Model prediction errors in CA50 of less than 1 °CA across all conditions were found. Modeling results of other combustion metrics such as combustion duration and indicated mean effective pressure are also highly satisfactory. In addition, the model has been shown to be capable of estimating the ringing intensity for most conditions.

The photochemical transformation processes occurring at the sea surface lead to the formation of low volatility organic compounds that contribute to new particle formation in the marine boundary la...

Zhundong coalfield is a super-large coal reserve, with high-alkali feature exacerbating ash deposition. Oxy-fuel combustion technology could propel the clean utilization of Zhundong high-alkali coal. While the ash deposition behavior of high-alkali coal under oxy-fuel condition has yet to be sufficiently investigated. The present study compared the differences of ash deposits between oxy-fuel and air combustion, and also examined the effects of oxygen content on ash deposition mechanism, employing a drop-tube furnace equipped with a specially designed sampling probe and some analysis methods, such as X—ray diffraction equipment, simultaneous thermal analyzer, etc. Experimental results indicated that ash deposition was weaker, with fewer contents of sodium chloride, calcium sulphate and less agglomeration ash in oxy-fuel atmosphere compared to the air case with same oxygen content. The content of the ash particle distributed in the range of 0–40 μm was up to 60% under oxy-fuel condition. The first weight loss of ash deposits, around 850 °C, was put down to the decomposition of carbonate and the second one, about 1150 °C, was ascribed to the decomposition of the sulphate minerals in the thermal process. Ash deposition worsened with more large particles (>120 μm), as the oxygen content rose. Sodium chloride content reached 9.7% with 50% oxygen content. The present study not only focuses on the morphology and chemical components, but also probes into the thermal volatility of ash deposits, which benefits the further understanding of the ash deposition mechanism and utilization of Zhundong high-alkali coal during oxy-fuel combustion.

Measurements by semivolatile thermal desorption aerosol gas chromatography (SV-TAG) were used to investigate how semivolatile organic compounds (SVOCs) partition among indoor reservoirs in (1) a manufactured test house under controlled conditions (HOMEChem campaign) and (2) a single-family residence when vacant (H2 campaign). Data for phthalate diesters and siloxanes suggest that volatility-dependent partitioning processes modulate airborne SVOC concentrations through interactions with surface-laden condensed-phase reservoirs. Airborne concentrations of SVOCs with vapor pressures in the range of C13 to C23 alkanes were observed to be correlated with indoor air temperature. Observed temperature dependencies were quantitatively similar to theoretical predictions that assumed a surface-air boundary layer with equilibrium partitioning maintained at the air-surface interface. Airborne concentrations of SVOCs with vapor pressures corresponding to C25 to C31 alkanes correlated with airborne particle mass concentration. For SVOCs with higher vapor pressures, which are expected to be predominantly gaseous, correlations with particle mass concentration were weak or nonexistent. During primary particle emission events, enhanced gas-phase emissions from condensed-phase reservoirs partitioned to airborne particles, contributing substantially to organic particulate matter. An emission event related to oven-usage was inferred to deposit siloxanes in condensed-phase reservoirs throughout the house, leading to the possibility of reemission during subsequent periods with high particle loading.

The GoAmazon 2014/5 field campaign took place in Manaus, Brazil, and allowed the investigation of the interaction between background-level biogenic air masses and anthropogenic plumes. We present in this work a box model built to simulate the impact of urban chemistry on biogenic secondary organic aerosol (SOA) formation and composition. An organic chemistry mechanism is generated with the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to simulate the explicit oxidation of biogenic and anthropogenic compounds. A parameterization is also included to account for the reactive uptake of isoprene oxidation products on aqueous particles. The biogenic emissions estimated from existing emission inventories had to be reduced to match measurements. The model is able to reproduce ozone and NOx for clean and polluted situations. The explicit model is able to reproduce background case SOA mass concentrations but does not capture the enhancement observed in the urban plume. The oxidation of biogenic compounds is the major contributor to SOA mass. A volatility basis set (VBS) parameterization applied to the same cases obtains better results than GECKO-A for predicting SOA mass in the box model. The explicit mechanism may be missing SOA-formation processes related to the oxidation of monoterpenes that could be implicitly accounted for in the VBS parameterization.

Volatility is one of the most important physical properties of organic aerosol (OA), as it determines the partitioning of its components between the vapor and particulate phases. Despite their atmo...

Volatile oils exhibit numerous biological activities including antimicrobial, wound-healing, and antioxidant. The domestic and medical use of these oils is, however, limited by their volatility, hy...

Solid polymer electrolytes (SPEs) with the advantages of high safety, low volatility, and the ability to suppress Li dendrites are highly desirable to be used in next generation high-safety and high-energy lithium-ion batteries. The exploration of SPEs with superior comprehensive properties has received extensive attention for high-performance all-solid-state batteries (ASSBs). Herein, a sandwich-like nanofibrous membrane-reinforced poly-caprolaclone diol and trimethyl phosphate (TMP) composite polymer electrolyte (CPE) has been designed by a facile "solvent-free" solution-casting method. Specifically, the flame-retardant TMP is employed as a plasticizer, which can improve the ionic conductivity effectively. The as-prepared solid electrolyte exhibits superior comprehensive performance in terms of high ionic conductivity, wide electrochemical window, good compatibility with lithium metal, and superior thermal stability. Furthermore, the assembled Li//LiFePO4 ASSBs with this solid CPE show outstanding cycling stability and high average discharge capacity at room temperature (30 °C). Undoubtedly, our study provides a new facile method and a qualified solid electrolyte material for next generation high-performance ASSBs.

Producing hydrogen by water electrolysis with solar and wind energy will be one of the main methods of hydrogen production. The inherent intermittency and volatility are, however, the biggest obsta...

Atmospheric water-soluble organic gases such as pyruvic acid are produced in large quantities by photochemical oxidation of biogenic and anthropogenic emissions and undergo water-mediated reactions in aerosols and hydrometeors. These reactions can contribute to aerosol mass by forming less-volatile compounds. Although progress is being made in understanding the relevant aqueous chemistry, little is known about the chemistry that takes place during droplet evaporation. Here, we examine the evaporation of aqueous pyruvic acid droplets using both the vibrating orifice aerosol generator (VOAG) and an electrodynamic balance (EDB). In some cases, pyruvic acid was first oxidized by OH radicals. The evaporation behavior of oxidized mixtures was consistent with expectations based on known volatilities of reaction products. However, independent VOAG and EDB evaporation experiments conducted without oxidation also resulted in stable residual particles; the estimated volume yield was 10–30% of the initial pyruvic acid. Yields varied with temperature and pyruvic acid concentration across cloud-, fog-, and aerosol-relevant concentrations. The formation of low-volatility products, likely cyclic dimers, suggests that pyruvic acid accretion reactions occurring during droplet evaporation could contribute to the gas-to-particle conversion of carbonyls in the atmosphere.

To investigate the short- and long-term accumulated emissions from a nuclear facility, charcoal air filter cartridges were exposed at a reactor site for seven days. The short-lived 131I adsorbed in these filters was measured by gamma counting immediately after the samples were retrieved. The very long-lived 129I was analyzed later by AMS. For this purpose, two methodologies were developed: an extraction method and direct analysis, i.e., inserting an aliquot of the filter carbon directly into the target piece. The former method used a system designed to avoid sample loss resulting from the high I2 species volatility. Iodine-125 was used as a tracer to monitor the efficiency of this extraction process. The direct method was based on our experience with charcoal in the analysis of 14C in Cs sputter ion sources. In this direct analysis, charcoal samples were first spiked with a known quantity of stable iodine (127I), in an excess over the quantity naturally present in the filter, and then pressed into targets. In this way, 129I concentrations from all the charcoal samples were quickly determined. In both methods, it was found that the atom concentration of 129I in these samples exceeded that of the 131I by 2–3 orders of magnitude. These studies demonstrate the effectiveness of the charcoal capture method as a diagnostic tool for monitoring the emissions from nuclear facilities. This approach may be extended for the detection of other long-lived radioactive isotopes, which would further expand the scope of such monitoring studies.

To improve the ablation resistance under the ultra-high temperature, the matrix of the carbon/carbon (C/C) composite was modified with a ternary ceramic of SiC–ZrC–TiC via reactive melt infiltration. The obtained ceramic matrix was composed of Zr-rich and Ti-rich solid solution phases of Zr1−xTixC and SiC. This composite exhibited an excellent ablation property at 2500 °C with low mass and linear ablation rates of 0.008 mg s−1 cm−2 and 0.000 μm s−1, respectively. The ablation mechanism was revealed with various microstructure characterizations and compared with those of C/C–SiC and C/C–TiC composites. Results showed that the degradations of these composites were primarily caused by the loss of the protective oxide scale via volatilization under the ultra-high temperature and flushing by high-speed airflow. The high ablation resistance of the C/C–SiC–ZrC–TiC composite was attributed to the protection of a multiphase oxide scale with high viscosity and low volatility.

Traditional amine solutions for CO2 capture are associated with many defects such as sacrificed CO2 capacities and high volatility. Herein, a new type of mixed solvent was constructed by diluting p...

Mixed halide hybrid perovskites are strong candidates for fabrication of efficient, stable and reproducible perovskite solar cells (PSCs). To restrain intrinsic volatility and ionic migration effec...

Formaldehyde is a volatile organic compound (VOC) with extensive applications, volatility, and toxicity, which have made it an important risk to human health even at low concentrations. Therefore, rapid detection of formaldehyde vapors in the environment is a necessity. Herein, we introduce a resistive gas sensor based on zeolitic imidazolate framework-8/multiwalled carbon nanotube (ZIF-8/MWCNT) for detection of formaldehyde vapors at room temperature. In this sensor, a low amount of MWCNTs was used in order to improve the electrical conductivity of the porous nanoparticles of ZIF-8. The sensor was fabricated by deposition of a thin layer of the nanocomposite onto interdigitated electrodes, and its sensing ability was investigated on exposure to formaldehyde vapors. The obtained sensor showed sensitive and fast responses to different concentrations of formaldehyde, and the sensor response to formaldehyde was higher than toward some other VOCs, including methanol, ethanol, acetone, and acetonitrile. Furthermore, because of the hydrophobic nature of ZIF-8, the effect of relative humidity on the gas-sensing performance was insignificant, which proves that this sensor is suitable for use under humid conditions.

Spray drying is one of the most broadly applicable and widely used methods of producing amorphous solid dispersions (ASDs). ASDs can improve the oral absorption of poorly water-soluble active pharmaceutical ingredients. Eudragit L100 is an appealing ASD excipient, due to its favorable impact on ASD physical stability and dissolution performance. However, spray drying Eudragit L100 can lead to high-aspect ratio filaments which reduce flowability, density and yield of the resulting powder. This negatively impacts downstream ASD performance and dosage form manufacturability. This work presents a mechanism for filament formation, which results in a particle engineering design space of key processing parameters, defined by a dimensionless parameter for assessing filament formation risk. Specifically, it was found that solution concentration, spray dryer inlet temperature and solvent volatility had the largest impact on controlling filament formation, based on their influence on the relative time scale to atomize versus droplet skinning during drying.

Ethanolamines have traditionally been used for capturing CO2 in a post-combustion carbon capture column. However, use of ethanolamines, due to their high volatility and solvent losses, is not sustainable. One of the ways in which the solvent loss occurs is in the form of aerosols from the top of the column. The mechanism, rate of nucleation, growth rate, and interaction leading to the formation of aerosols, although essential for better process design, remain obscure. Using molecular dynamics simulations, we herein, analyze formation of aerosols in columns based on aqueous monoethanolamine (MEA), aqueous methyldiethanolamine (MDEA) and their mixtures, using reference, pilot-scale, and industrial-scale data. In particular, the nucleation rate and cluster growth analysis were performed for five different cases. The results show CO2 concentration had a strong influence on rate of aerosol formation, a factor that can be easily controlled for better process design. Moreover, the interactions within the formed ...

In this work, we study the effect of fluorosubstitution on the crystal structure of phthalocyanines of copper, cobalt, and vanadyl and analyze the correlations between the structure and volatility ...

Prior studies have shown that neglecting the vapor wall loss could lead to the underestimation of the secondary organic aerosol (SOA) yields in smog chamber experiments. The majority of the previous studies investigated vapor wall loss of a wide range of semi-volatile organic vapors at room temperatures using extensive chemical analysis. This study poses a question: Can vapor wall deposition in a smog chamber be observed only using physical measurements of aerosol properties? This study assesses the significance of vapor wall loss using only the size evolution of pure organic compound particles. To our knowledge, this technique is used for the first time in assessing the vapor wall loss of chemical species in chamber experiments. Dark experiments were conducted by injecting pure levoglucosan particles into an outdoor smog chamber at multiple ambient temperatures, ranging from –10°C to +15°C. Peak diameter analysis revealed levoglucosan particles shrunk by ~37% at 15°C and ~20% at 10°C experiments, whereas no shrinkage was observed at temperatures below 0°C suggesting significant vapor wall loss of levoglucosan at warmer temperatures (> 10°C). Two-Moment Aerosol Sectional (TOMAS) and additional simple kinetic model simulations suggest that the effects of temperature on vapor wall loss can primarily be explained by the change in saturation vapor pressure of the organic compound and that the lack of apparent vapor wall loss of levoglucosan below 0°C was due to kinetics, i.e., slow evaporation relative to the chamber experiment timescales. The same approach can be applied to other organic species to expand the range of volatility relevant to chamber experiments.

With the aim to render assistance to future experiments on the production and investigation of chemical properties of carbonyl compounds of element 109, Mt, calculations of the molecular properties of M(CO)4 and MH(CO)4, where M = Rh, Ir, and Mt, and of the products of their decomposition, M(CO)3 and MH(CO)3, were performed using relativistic Density Functional Theory and Coupled-Cluster methods implemented in the ADF, ReSpect and DIRAC software suites. According to the results, MH(CO)4 should be formed at experimental conditions from the M atom with a mixture of CO and He gases. The calculated first M–CO bond dissociation energies (FBDE) of Mt(CO)4 and MtH(CO)4 turned out to be significantly weaker than those of the corresponding Ir homologs. The reason for that is the relativistic destabilization and expansion of the 6d AOs, responsible for both the weaker σ(CO) → d(M) forth and d(M) → π(CO) back electron density donation in the Mt compounds. The relativistic FBDEs of MH(CO)4 have, therefore, a Λ-shape behavior in the row Rh–Ir–Mt, while the non-relativistic values increase towards Mt. Using the results of the calculations and a molecule–slab interaction model, the adsorption enthalpies, ΔHads, serving as a measure of volatilty, of the group-9 carbonyl hydrides on surfaces of quartz and Teflon were estimated. Accordingly, MtH(CO)4 should be almost as volatile as RhH(CO)4 and IrH(CO)4; however, its interaction with the surfaces should be somewhat weaker than that of IrH(CO)4. It will, therefore, be difficult to distinguish between group-9 MH(CO)4 species by measuring their ΔHads on surfaces of Teflon and quartz with an experimental uncetainty of ±3 kJ mol−1. The trends in the properties of group-9 carbonyl hydrides should be similar to those of group-6, 7 and 8 carbonyl compounds including those of Sg, Bh and Hs, respectively.

Cobalt content in Li-ion battery cathodes has become a top concern due to its price volatility and limited source availability. Low-cobalt, Ni-rich active materials are promising candidates for next-generation cathodes due to their high capacities, and water-based processing of these materials can further reduce both cost and environmental impact. We systematically evaluated the water compatibility of four different LiNixMn1-x-yCoyO2 (NMC) powders with increasing nickel contents. Comprehensive characterization verified there is no major change to their bulk structures, and only slight surface modifications related to the removal of contaminant species. For the first time, we demonstrate that LiNi0.8Mn0.1Co0.1O2 (NMC 811) cathodes can be formulated in water and cycled 1000 times in full pouch cells with excellent capacity retention (~70% compared to ~76% for NMP-processed cells). When implemented in future battery production lines, aqueous processing of Ni-rich NMC will simultaneously enable cost reductions and higher cell energy densities.

We for the first time have found that PEG-based DESs could volatilize at room temperature and atmospheric pressure. The mass loss from long-term evaporation of PEG-based DESs at 298.15 K for 1000 min could reach as high as 30.5% mass loss, ca. 6 times that of short-term evaporation (5.1% mass loss). Generally, the vaporization enthalpy of PEG-based DESs is found to lie between that of common organic solvents and that of ionic liquids, while some PEG-based DESs could be more volatile than common organic solvents. The evaporation of PEG-based DESs could be ascribed to their volatile constituents; however, the evaporation rate of each constituent is found to be very different. This is the first discovery of the higher volatility of PEG-based DESs at room temperature and atmospheric pressure.