Evaporation Of Components Research Articles

Vapor-liquid equilibrium data of binary mixtures of 1-hexanol, 1-heptanol, 1-nonanol and 1,3-propanediol at P = 101.3 kPa using differential scanning calorimetry (DSC)

In this study, the vapor-liquid equilibrium data for of six binary pairs made up from 1-hexanol, 1-heptanol, 1-nonanol and 1,3-propanediol at P = 101.3 kPa are presented. Differential scanning calorimetry (DSC) was used to obtain the equilibrium data for each pair binary system. The experimental data were correlated using different activity coefficient models. Results showed that the binary pair consisting of 1-nonanol and 1,3-propanediol was the only pair that contains an azeotrope point. This azeotrope occurred at a 1-nonanol molar composition of 0.4501 and temperature of 474.44 K. The experimental data showed high level of accuracy for the pure component vapor pressure, compared to reported values in literature using differential thermal analysis and other conventional methods. Also, a modified van Ness test showed that the gathered experimental equilibrium data for mixtures had a high level of thermodynamic correlation accuracy.

Novel instrument to generate representative e-cigarette vapors for physicochemical particle characterization and in-vitro toxicity

The use of “electronic cigarettes” (e-cigs) has exponentially increased during the last decade. This drastic growth has been observed in smokers and never smokers, women and teenagers, with indicators for adverse effects related to nicotine, but also to e-liquid and vapor components. The aerosol characteristics depend on the e-cig features. Therefore, the introduction of many different e-cig types on the market leads to concerns regarding their potential health effects. Our study aims to develop an instrument to generate representative vapors from e-cigarette devices, characterize the physicochemical properties of the aerosols and elucidate the adverse effects of inhaled vapors on normal human airway epithelia. E-cig vapors were produced using a specially developed aerosol generation instrument mimicking user puffing behavior. Aerosol particle size distribution and concentration were characterized with a Scanning Mobility Particle Sizer. Air-liquid interface cultures of differentiated human bronchial epithelial cells were exposed to 1 puff topography, i.e. to 21 puffs of 3 s with 22-second puff intervals using the Nano-Aerosol Chamber for In-Vitro Toxicity, which simulates particle deposition in the respiratory tract. Cell morphology was evaluated by light microcopy and induction of cell death by release of lactate dehydrogenase at 4 and 24 h after aerosol exposure. Particle size in e-cig generated aerosols ranged from 20 to 430 nm and concentrations exceeded 1 × 106 particles/cm3. Deposited particle doses were 0.9–3 μg/cm2, depending on e-device type and number of puffs. A single exposure to e-cig vapors caused changes in epithelial cell shape but no massive cell death. We successfully developed an aerosol generation system to produce and deposit realistic vapors from e-cigs. The results obtained indicate that a single exposure to e-cig aerosols affects epithelial morphology and slightly increases cell death. Our interdisciplinary approach combining aerosol technology and biology allows identifying adverse effects of e-cigs to the respiratory tract in vitro.

Surface chemistry of electronic cigarette electrical heating coils: Effects of metal type on propylene glycol thermal decomposition

IntroductionCarbonyls, a class of compounds strongly linked to pulmonary disease in smokers, are probably the most reported non-nicotine toxicants found in electronic cigarette (ECIG) aerosols. Reported emissions vary from negligible quantities to those far exceeding combustible cigarettes. Observations of high emissions are commonly attributed to “dry puffing”, whereby the ECIG heating filament runs dry of liquid and reaches temperatures that induce thermal degradation of the ECIG vapor components at the filament’s metal surface. Using a pyrolysis flow reactor, in this study we examined the potential role of surface chemistry in the formation of carbonyl compounds in ECIGs, and whether the different commercially available filament materials could potentially impact their toxicant emissions through catalysis. This information could inform nascent efforts to regulate the design of ECIGs for public health ends. MethodsNitrogen or air saturated with propylene glycol vapor was drawn through a temperature and residence-time controlled tubular quartz pyrolysis flow reactor in which nichrome, Kanthal, or stainless steel ECIG heating filament wires were inserted. A control condition with no inserted wire was also included. Concentrations of carbonyl products at the reactor outlet were measured as a function of temperature, heating filament wire material, and carrier gas composition (N2 vs air). Carbonyls were sampled using DNPH cartridges and analyzed by HPLC. ResultsECIG heating filament wires were found to have a strong catalytic effect. Carbonyl formation initiated at temperatures lower than 250 °C in the presence of the metallic wires, compared to 460 °C without them. Carbonyl formation was found to be a function of the material of construction, and whether the wire was new or aged. New nichrome wires were the least reactive, but when aged they exhibited the highest reactivity. Carbonyls were formed via dehydration or oxidation reactions of PG. ConclusionsCarbonyl formation chemistry is catalyzed by commonly used ECIG heating filament materials, at temperatures that are well below those expected during “dry puffing”. The variability in the distribution and yield of carbonyl compounds across ECIG filament materials suggests that this heretofore unaccounted variable may partially explain the wide ranges reported in the literature to date. More importantly, it suggests that ECIG construction materials may be an important variable for regulations designed to protect public health.

Mixed Vapor Generation Device for delivery of homemade explosives vapor plumes

While there is a large body of research on the properties and detection of traditional military high explosives and propellant low explosives, there is a dearth of research on homemade explosive (HME) materials, though they are prevalent today. The safety of working with these materials in the laboratory is the greatest limiting factor preventing HME research. A vapor delivery tool, the Mixed Vapor Generation Device (MV-Gen), was designed to safely contain the individual solid or liquid components that often compose homemade explosives vapor plumes and deliver the mixed component vapors for instrumental sampling and analysis. Within the MV-Gen, each component is separated and only the vapors mix as they are carried through the device by flowing air. The resulting mixed vapor is representative of either mixed explosive material or bulk explosives. Component materials are held in up to four individual, removable vials with vapor concentrations controlled by vial orifice size, temperature, and diluent airflow. The total concentration can be adjusted by altering vial temperature via a thermal water jacket surrounding the entirety of the device, or by adjusting the flow rate of diluent air through the device. The MV-Gen was evaluated first with surrogate compounds, followed by two types of homemade explosives, to include a binary explosive mixture and a peroxide explosive. To evaluate the device, vapors were cold-trapped on an online sampling system and analyzed by gas chromatography/mass spectrometry. It was determined that the device yielded reproducible vapor concentrations of both single and mixed components, and the ratio of these vapors can be easily adjusted to mimic varying forms of homemade explosives.

Binary adsorption equilibrium and breakthrough of toluene and cyclohexane on macroporous and hypercrosslinked polymeric resins

Adsorption-based separation is one of the most widely used methods in treating gasoline vapor. For effective control of gasoline vapor emission, the total concentration of non-methane hydrocarbons (NMHC) and the specific component such as toluene must meet the emission limit values. In this study, hypercrosslinked polymeric resin (Hyper-resin) and macroporous polymeric resin (Macro-resin) were selected as adsorbents. Toluene and cyclohexane were chosen as the representative of alkanes and aromatic hydrocarbons components of gasoline vapor. Pure and binary component adsorption isotherms of toluene and cyclohexane on two resins were measured by head space analysis method. Breakthrough data for binary system were obtained at the different concentrations of toluene (12–46 mg/L) and cyclohexane (15 mg/L and 102 mg/L) using a fixed-bed reactor. The results indicate that adsorption equilibria of binary component can be predicted by ideal adsorbed solution theory (IAST) with the average relative error lower than 15% using the pure component adsorption isotherm data. Hyper-resin provides higher selectivity to toluene than Macro-resin in binary equilibrium and breakthrough system. Moreover, the breakthrough adsorption capacities of pure component (toluene and cyclohexane) and their mixture on Hyper-resin are higher than those on Macro-resin, suggesting Hyper-resin would be a promising adsorbent for treating gasoline vapor.

Water transport mechanisms for salt-rejecting membranes driven by soil-water potentials

Water transport may be driven across dense thin-films when contacted with soil to create a non-pressure driven desalination process; however, the roles played by the different soil-water potential components (matric, osmotic, and vapor pressure) in driving water flux are not completely understood. Bench-scale tests were done using a reverse osmosis membrane and three different soils: sand, sandy-loam, and kaolin clay. The diverse physical and chemical characteristics of these soils were used to quantify membrane performance (water flux) and relate it to the magnitudes of the three soil-water potentials. Water flux was highest at initial contact between the soil and membrane, and then declined to reach a steady-state value, irrespective of soil type. The highest steady-state water flux, 1.8 l/m2/h, was measured for the pure clay system. Matric and osmotic potential gradients were the primary drivers for water flux, while vapor pressure played a minor role. Membrane orientation (active or support side facing the soil) and internal concentration polarization were also identified as determinants of water flux.

Vaporization and thermodynamics of ceramics based on the La2 O3 -Y2 O3 -HfO2 system studied by the high-temperature mass spectrometric method.

Materials based on the La2 O3 -Y2 O3 -HfO2 system are promising for the production of highly refractory ceramics, e.g., thermal barrier coatings and molds for casting of elements of gas turbine engines. When these ceramics are synthesized or used at high temperatures, selective vaporization of components may take place, resulting in changes in the physicochemical properties of the materials. Consequently, development of materials based on the La2 O3 -Y2 O3 -HfO2 system requires information on vaporization in this system as well as on its thermodynamics, without which prediction and modeling of their physicochemical properties are impossible. Vaporization processes and thermodynamic properties in the La2 O3 -Y2 O3 -HfO2 system were studied by the high-temperature Knudsen effusion mass spectrometric method using a MS-1301 mass spectrometer. Electron ionization of vapor species was employed at an ionization energy of 25eV. The samples under study and reference substances were vaporized from a tungsten twin effusion cell. At 2337K the main vapor species over samples in the La2 O3 -Y2 O3 -HfO2 system were shown to be LaO, YO and O. The partial pressures of the vapor species mentioned and the La2 O3 and Y2 O3 activities in the samples were obtained at 2337K. The Gibbs energies of mixing and excess Gibbs energies were found in the solid solution of this system. Vaporization of ceramics based on the La2 O3 -Y2 O3 -HfO2 system at 2337K led to selective transition of La2 O3 and Y2 O3 to the gaseous phase, with the La2 O3 vaporization rate being higher than that of Y2 O3 . The directions of composition changes of samples due to their vaporization at 2337K were determined. In the solid solution of this system negative deviations from ideal behavior were found. The ability to estimate the excess Gibbs energies in the solid solution of the La2 O3 -Y2 O3 -HfO2 system by the Kohler method was shown.

Accounting for the Effect of Noncondensing Gases on Interphasic Heat and Mass Transfer in the Two-Fluid Model Used in the KORSAR Code

A model is presented of the interphasic heat and mass transfer in the presence of noncondensable gases for the KORSAR/GP design code. This code was developed by FGUP NITI and the special design bureau OKB Gidropress. It was certified by Rostekhnadzor in 2009 for numerical substantiation of the safety of reactor installations with VVER reactors. The model is based on the assumption that there are three types of interphasic heat and mass transfer of the vapor component: vapor condensation or evaporation on the interphase under any thermodynamic conditions of the phases, pool boiling of the liquid superheated above the saturation temperature at the total pressure, and spontaneous condensation in the volume of gas phase supercooled below the saturation temperature at the vapor partial pressure. Condensation and evaporation on the interphase continuously occur in a two-phase flow and control the time response of the interphase heat and mass transfer. Boiling and spontaneous condensation take place only at the metastable condition of the phases and run at a quite high speed. The procedure used for calculating condensation and evaporation on the interphase accounts for the combined diffusion and thermal resistance of mass transfer in all regimes of the two-phase flow. The proposed approach accounts for, in a natural manner, a decrease in the rate of steam condensation (or generation) in the presence of noncondensing components in the gas phase due to a decrease (or increase) in the interphase temperature relative to the saturation temperature at the vapor partial pressure. The model of the interphase heat transfer also accounts for the processes of dissolution or release of noncondensing components in or from the liquid. The gas concentration at the interphase and on the saturation curve is calculated by the Henry law. The mass transfer coefficient in gas dissolution is based on the heat and mass transfer analogy. Results are presented of the verification of the interphase heat and mass transfer used in the KORSAR/GP code based on the data on film condensation of steam-air flows in vertical pipes. The proposed model was also tested by solving a problem of nitrogen release from a supersaturated water solution.

Features of Large Magmatic–Hydrothermal Systems in Japan: Characteristics Similar to the Tops of Porphyry Copper Deposits

AbstractVolcanic complexes in Japan such as Kusatsu Shirane, Honshu, and Kuju‐Hatchobaru and Kirishima, Kyushu, host active magmatic–hydrothermal systems that are several kilometers in diameter and typically asymmetric to the intrusive center. Their heat flow is driven by multiple intrusions at <5–10 km depth over a period on the order of ~105 years. These hydrothermal systems consist of advecting fluids of magmatic origin (either vapor with acidic components condensed into meteoric water, or a subsequent liquid of varying reactivity) that interact with convecting meteoric water. The amount of the magmatic component depends on location relative to the intrusive center, local controls on permeability, and the temporal evolution of the intrusions. The proportion of meteoric water diluent typically increases from proximal to distal locations (over several kilometer distance), and with time after intrusion (> several thousands of years). Some of the neutral pH solutions in these large hydrothermal systems, up to ~5 km from volcanic vents, support geothermal energy developments, with strong structural control on fluid flow. Near active volcanic vents, the magmatic vapor component of hydrothermal systems can form acidic condensates (pH ~ 1.5) that are responsible for strong alteration of the host rock. The resulting residual quartz and advanced argillic minerals are typical of shallow‐formed lithocap alteration that is associated with deeper porphyry copper deposits in similar arc‐hosted volcanic settings. Around the world, this near‐surface lithocap alteration, influenced by structures as well as lithology, may be barren in metals, even where associated with mineralized porphyry intrusions at depth. Such intrusion‐proximal alteration is widespread in both active and extinct settings in Japan. In addition, distal geothermal hot springs typically have a magmatic water component, albeit minor, with a pH that varies from ~3 to near‐neutral; deep alteration intersected in drill holes is characterized by alunite–dickite–pyrophyllite or chlorite–wairakite, respectively. These alteration assemblages are typical of their extinct equivalents, intermediate sulfidation epithermal veins, with mineralogical complexities caused by temporal evolution as well as spatial variation (e.g. along different structures). Such active and extinct magmatic–hydrothermal systems signify the presence of shallow degassing or degassed intrusions, respectively. Where similar intrusions in volcanic arcs around the world are eroded to ~1 to 2 km depth, the tops of porphyry copper deposits are commonly exposed, marked by a transition of white mica upward to pyrophyllite‐dominant alteration. Active magmatic–hydrothermal systems on the flanks of arc volcanoes in Japan are dynamic – both cycling as well as evolving – and share characteristics with extinct systems that host epithermal and porphyry ore deposits.

Normal and grazing incidence pulsed laser deposition of nanostructured MoSx hydrogen evolution catalysts from a MoS2 target

Pulsed laser ablation of a MoS2 target causes enhanced splashing of the material. So, for MoSx films obtained by pulsed laser deposition (PLD) in the conventional normal incidence (NI) configuration, their typical morphology is characterized by an underlying granular structure with an overlayer of widely dispersed spherical Mo and MoSx particles possessing micro-, sub-micro- and nanometer sizes. We investigated the possibility of using high surface roughness, which occurs due to particle deposition, as a support with a large exposed surface area for thin MoSx catalytic layers for the hydrogen evolution reaction (HER). For comparison, the HER performance of MoSx layers formed by grazing incidence (GI) PLD was studied. During GI-PLD, a substrate was placed along the direction of laser plume transport and few large particles loaded the substrate. The local structure and composition of thin MoSx layers formed by the deposition of the vapor component of the laser plume were varied by changing the pressure of the buffer gas (argon, Ar). In the case of NI-PLD, an increase in Ar pressure caused the formation of quasi-amorphous MoSx (x ≥ 2) films that possessed highly active catalytic sites on the edges of the layered MoS2 nanophase. At the same time, a decrease in the deposition rate of the MoSx film appeared due to the scattering of the vapor flux by Ar molecules during flux transport from the target to the substrate. This effect prevented uniform deposition of the MoSx catalytic film on the surface of most particles, whose deposition rate was independent of Ar pressure. The scattered vapor flux containing Mo and S atoms was a dominant source for MoSx film growth during GI-PLD. The thickness and composition distribution of the MoSx film on the substrate depended on both the pressure of the buffer gas and the distance from the target. For 1.0–2.5 cm from the target, the deposition rate was quite sufficient to form S-enriched quasi-amorphous MoSx (2.5 < x < 6) catalytic films that consisted of densely packed 30–50 nm nanoparticles. The GI-PLD films possessed a greater density of catalytically active sites with a distinct local atomic configuration including edge sites of the layered MoS2 nanophase and diverse S ligands in the amorphous phase, which contained Mo3-S clusters. At a modest loading of ∼300 μg/cm2 on glassy carbon substrates and an overpotential of -140 mV, these films activated H2 production with geometric current densities up to −10 mA/cm2.

Light-activated gas sensing activity of ZnO nanotetrapods enhanced by plasmonic resonant energy from Au nanoparticles

High response and low working temperature are two essential requirements for promising chemi-resistive gas sensors, considering the issues of practical usage, safety, stability, energy conservation, etc, while traditional sensors usually work at high temperatures. One typical approach to solve this drawback is using photon activated process, but its overall activation response is not high enough for room-temperature operation. Utilization of localized surface plasmon resonance (LSPR) can increase light absorption and energetic carrier generation. Based on this, we developed a high-response and room-temperature sensor by decorating 3-dimensional-structured ZnO nanotetrapods (ZnO NTPs) with Au nanoparticles (Au NPs) through a facile sputtering-annealing process. Compared to pure ZnO NTPs, this hybrid nanostructure enhanced detection of volatile vapor components including ethanol, formaldehyde, acetone and methanol under 6 mW/mm2 white light illumination at room temperature. Representatively, the sensing response increased remarkably from 5.5 to 62 towards 500 ppm ethanol vapor. It also exhibits decent long-term stability and a better sensing performance than a commercial thermal-activated alcohol sensor operating at an optimal temperature of 370 °C. The reported LSPR assisted approach holds strong potential for practical devices and pave a new way for the development of room-temperature gas sensor with high-performance.

Phagocytosis and Inflammation: Exploring the effects of the components of E-cigarette vapor on macrophages.

E‐cigarettes are perceived as harmless; however, evidence of their safety is lacking. New data suggests E‐cigarettes discharge a range of compounds capable of physiological damage to users. We previously established that cigarette smoke caused defective alveolar macrophage phagocytosis. The present study compared the effect E‐cigarette of components; E‐liquid flavors, nicotine, vegetable glycerine, and propylene glycol on phagocytosis, proinflammatory cytokine secretion, and phagocytic recognition molecule expression using differentiated THP‐1 macrophages. Similar to CSE, phagocytosis of NTHi bacteria was significantly decreased by E‐liquid flavoring (11.65–15.75%) versus control (27.01%). Nicotine also decreased phagocytosis (15.26%). E‐liquid, nicotine, and E‐liquid+ nicotine reduced phagocytic recognition molecules; SR‐A1 and TLR‐2. IL‐8 secretion increased with flavor and nicotine, while TNF α, IL‐1β, IL‐6, MIP‐1α, MIP‐1β, and MCP‐1 decreased after exposure to most flavors and nicotine. PG, VG, or PG:VG mix also induced a decrease in MIP‐1α and MIP‐1β. We conclude that E‐cigarettes can cause macrophage phagocytic dysfunction, expression of phagocytic recognition receptors and cytokine secretion pathways. As such, E‐cigarettes should be treated with caution by users, especially those who are nonsmokers.

Development of Molecular Distillation Based Simulation and Optimization of Refined Palm Oil Process Based on Response Surface Methodology

The deodorization of the refined palm oil process is simulated here using ASPEN HYSYS. In the absence of a library molecular distillation (MD) process in ASPEN HYSYS, first, a single flash vessel is considered to represent a falling film MD process which is simulated for a binary system taken from the literature and the model predictions are compared with the published work based on ASPEN PLUS and DISMOL. Second, the developed MD process is extended to simulate the deodorization process. Parameter estimation technique is used to estimate the Antoine’s parameters based on literature data to calculate the pure component vapor pressure. The model predictions are then validated against the patented results of refining edible oil rich in natural carotenes and vitamin E and simulation results were found to be in good agreement, within a ±2% error of the patented results. Third, Response Surface Methodology (RSM) is employed to develop non-linear second-order polynomial equations based model for the deodorization process and the effects of various operating parameters on the performance of the process are studied. Finally, an optimization framework is developed to maximize the concentration of beta-carotene, tocopherol and free fatty acid while optimizing the feed flow rate, temperature and pressure subject to process constrains. The optimum results of feed flow rate, temperature, and pressure were determined as 1291 kg/h, 147 °C and 0.0007 kPa respectively, and the concentration responses of beta- carotene, tocopherol and free fatty acid were found to be 0.000575, 0.000937 and 0.999840 respectively.

Determination of thermophysical properties of 45% Pb‒55% Bi alloy. Thermodynamic simulation

The thermophysical properties of 45% Pb‒55% Bi alloy were studied using thermodynamic simulation. Vapor pressure, partial pressures of the components of vapor, heat capacity, entropy, enthalpy, and the thermal conductivity of an alloy depending on temperature were determined. A comparison of the results from published data was made.

Robust sacrificial polymer templates for 3D interconnected microvasculature in fiber-reinforced composites

A promising pathway for multifunctionality in fiber-composites is to mimic biological vasculature that enables living organisms with concerted homeostatic functions. In this paper, newfound material and processing advancements in vaporization of sacrificial components (VaSC), a technique for creating inverse replica architectures via thermal depolymerization of a sacrificial template, are established for enhanced vascular composites manufacturing. Sacrificial poly(lactic acid) with improved distribution of catalytic micro-particles is extruded into fibers for automated weaving and filament feedstock for 3-D printing. Fiber drawing after extrusion improves mechanical robustness for high-fidelity, composite preform weaving. Joining one-dimensional (1D) interwoven fibers with printed sacrificial (2D) templates affords three-dimensional (3D) interconnected networks in a fiber-composite laminate that inherits damage-tolerant features found in natural vasculatures. In addition to providing a conduit for enhanced functionality, the sacrificial templating techniques are compatible with current composites manufacturing processes, materials, and equipment.

Experimental investigation of CO2-oil interactions in tight rocks: A Montney case study

This paper presents comprehensive rock-fluid experiments to study the possibility of oil recovery improvement when CO2 is injected as a fracturing fluid in the Montney tight-oil play, located in the Western Canadian Sedimentary Basin. This study consists of four phases: In phase 1, we conduct constant composition expansion (CCE) tests with different CO2 concentrations using a PVT cell. In phase 2, we visualize CO2-oil interactions at reservoir pressure and temperature in a custom-designed visual cell. Then, we conduct SEM/EDS analysis on the solid precipitates in the visual cell due to CO2-oil interactions. In phase 3, we soak the oil-saturated core plugs in the visual cell, pressurize the cell with CO2, and measure the oil recovery. In phase 4, we conduct cyclic CO2 tests using a core flooding system, and measure the oil recovery.The results of the CCE tests conducted using the PVT cell and visualization tests conducted using the visual cell show that CO2 can significantly dissolve into and expand the Montney oil. The results of the CO2 soaking tests in the visual cell show that oil swelling and vaporization of oil components into CO2 phase are the main production mechanisms. The results of cyclic CO2 process using the core flooding system show that the oil swelling due to CO2-oil interactions, solution CO2 drive, and oil viscosity reduction lead to high oil recovery factor from the oil-saturated core plugs. In addition, we observe solid precipitates due to CO2-oil interactions at the bulk-phase conditions in the visual cell. SEM/EDS analysis on the solid precipitates show the existence of carbon and sulfur, the main components of asphaltene. The results of IP-143 test confirm the formation of asphaltene when the Montney oil contacts CO2 at reservoir conditions.

Application of Novel Pyrolysis Reactor Technology to Concentrate Bio-oil Components with Antioxidant Activity from Tobacco, Tomato and Coffee Ground Biomass

To make biomass conversion to fuels more cost-effective, value-added products, including pharmaceuticals, should be produced from agricultural residues. The objectives of this study were (1) to investigate the antioxidant properties of bio-oil produced from the pyrolysis of biomass and (2) to concentrate and identify antioxidant compounds from the bio-oil. This study used a two stage mechanically fluidized reactor (MFR) where the first stage, termed one-dimensional (1-D), produces vapors with varying chemical composition based on the reactor temperature while the two-dimensional (2-D) stage, separates vapor components according to their condensation temperature. Tobacco leaf (Nicotiana tabacum), tomato plant (Solanum lycopersicum) and spent coffee (Coffea arabica) grounds (<1 mm) were pyrolyzed at a heating rate of 10 °C/min from ambient to 565 °C. The 400–565 °C reactor temperature cuts of all three biomass bio-oils from 1-D MFR pyrolysis produced the highest amount of antioxidant activity compared to the other bio-oil cuts and the 2-D MFR pyrolysis of tomato plant bio-oil collected in the 120 °C condenser had the highest concentration of antioxidants. The 50% 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging potential (IC50 value) of the reference compound ascorbic acid and tomato bio-oil cut collected in the 120 °C condenser was 138 µg/mL versus 37 mg/mL, respectively. The gas chromatography–mass spectrometry (GC–MS) analysis identified 2-furanmethanol, phenol and glucose in the tomato bio-oil. The findings indicate the two stage MFR process can be used to concentrate antioxidants during bio-oil production by reactor and condenser temperature controls thus providing a useful tool for producing value-added compounds while processing agricultural residues.

Optimization of the vaporization of flavour components during wort boiling in the brewery by implementing a rectification column

Optimization of the vaporization of flavour components during wort boiling in the brewery by implementing a rectification column

Phase-formation mechanisms on composite oxide surfaces in thermostimulated segregation processes

The features of phase-formation mechanisms (PFMs) inherent to various temperature stages of surface phase creation are discussed with the locality of thermostimulated surface heterosegregation processes taken into account. The contributions of diffusion and sublimation processes to PFMs are estimated. It is demonstrated that pressure (vacuum) affects diffusion, adsorption, sublimation, and chemical reactions during thermostimulated segregation. The segregant type and inclination to segregation are predicted for compounds with a substantial difference between the partial pressures of the vapors of constituent components. The general PFM on the composite-oxide surface as a result of segregation is proposed.

Improved methodologies for continuous-flow analysis of stable water isotopes in ice cores

Abstract. Water isotopes in ice cores are used as a climate proxy for local temperature and regional atmospheric circulation as well as evaporative conditions in moisture source regions. Traditional measurements of water isotopes have been achieved using magnetic sector isotope ratio mass spectrometry (IRMS). However, a number of recent studies have shown that laser absorption spectrometry (LAS) performs as well or better than IRMS. The new LAS technology has been combined with continuous-flow analysis (CFA) to improve data density and sample throughput in numerous prior ice coring projects. Here, we present a comparable semi-automated LAS-CFA system for measuring high-resolution water isotopes of ice cores. We outline new methods for partitioning both system precision and mixing length into liquid and vapor components – useful measures for defining and improving the overall performance of the system. Critically, these methods take into account the uncertainty of depth registration that is not present in IRMS nor fully accounted for in other CFA studies. These analyses are achieved using samples from a South Pole firn core, a Greenland ice core, and the West Antarctic Ice Sheet (WAIS) Divide ice core. The measurement system utilizes a 16-position carousel contained in a freezer to consecutively deliver ∼ 1 m × 1.3 cm2 ice sticks to a temperature-controlled melt head, where the ice is converted to a continuous liquid stream and eventually vaporized using a concentric nebulizer for isotopic analysis. An integrated delivery system for water isotope standards is used for calibration to the Vienna Standard Mean Ocean Water (VSMOW) scale, and depth registration is achieved using a precise overhead laser distance device with an uncertainty of ±0.2 mm. As an added check on the system, we perform inter-lab LAS comparisons using WAIS Divide ice samples, a corroboratory step not taken in prior CFA studies. The overall results are important for substantiating data obtained from LAS-CFA systems, including optimizing liquid and vapor mixing lengths, determining melt rates for ice cores with different accumulation and thinning histories, and removing system-wide mixing effects that are convolved with the natural diffusional signal that results primarily from water molecule diffusion in the firn column.