As large-scale peat burning emissions can severely impact the environment and human health, it is crucial to assess the characteristics of smoke aerosol at the source and at down-wind locations. From March until late summer in 2014, the Tver region, north of the city of Moscow, was considerably affected by long-lasting peat bog fires. Peat bog smoldering emissions from three types of smoke (underground, inside grass, and above grass) were analyzed by an extensive suite of instrumentation that sampled and measured their optical and chemical properties. The particle composition was characterized by organic species with high OC/EC ratios (10–20), with water-soluble organic carbon (WSOC) and levoglucosan (Lev) comprising the largest fraction, up to 30 and 9

Reliable assessment of the impact of Siberian boreal forest wildfires on the environment and climate necessitates an improved understanding of microphysical and chemical properties of emitted aerosols. Smoldering, flaming and mixed fires of typical Siberian biomass (pine and debris) were simulated during a small-scale study in a Large Aerosol Chamber (LAC). Individual particle analysis of PM10 and PM2.(5) smoke morphology and elemental composition revealed a strong dependence on combustion temperature, i.e., a dominant abundance of soot agglomerates versus roughly spherical organic particles in the flaming and smoldering phase, respectively. Cluster analysis of smoke microstructure was used to apportion the emitted particles into major characteristic groups: Soot and Organic, which accounted for around 90% and 60% of total particle numbers emitted from the flaming and smoldering fires, respectively. Carbon fractions and inorganic ion analysis supported the identification of particle types representative of combustion phase and biomass type. Elemental carbon (EC) particles from flaming fires comprised approximately 25% of Group Soot, in good agreement with a high EC fraction in total carbon of around 65% and low organic carbon (OC)/EC ratio near 0.5. Smoldering fires of pine and debris produced exclusively organic particles with high OC/EC ratios of 194 and 34, respectively. Small quantities of elemental constituents in biomass were vaporized during combustion and produced internally/externally mixed fly ash in Group Ca-, Si-, and Fe-rich of significantly less abundance. Ca, Cl, S, and Mg were more frequently distributed elements in pine than debris smoke. Sulfates and nitrates produced from gas-to-particle reactions formed Group S- and N-rich. During time evolution of smoke volatile inorganic compounds were condensed as potassium chlorides and sulfates into a newly formed Group K, Cl-rich. Quantification of Siberian biomass smoke microstructure by chemical micromarkers enables aerosols to be classified with respect to a source type assigned to Siberian wildfires.

Aerosol particles significantly impact the regional environment, including climate change, specifically in periods of extensive biomass burning. The major agricultural and domestic combustion emission sources were assessed in near-source and ambient monitoring campaigns in northwestern Vietnam during the dry season. The composition and microstructure of on-field burning and cooking emissions were analyzed with a variety of techniques. A wide range of observed PM_(2.5) mass concentrations was categorized according to the smoke level, supported by the evolution of carbon fractions (OC and EC) as well as ionic species and molecular tracers (K^+, levoglucosan, and mannosan). The OC/EC and individual organic compound ratios on days with high smoke levels indicate smoldering combustion of softwood and other local biomass species, impacting aerosol composition at the regional level. Acid and non-acid carbonyls, carboxylates, and aliphatic carbon functionalities in the PM_(2.5) size fraction evolved with increasing smoke intensity, together with carbonates in coarse (PM_(1-2.5) and PM_(2.5-10)) size fractions, indicating a large impact of smoke emissions and soil lifted up by the intense fires. Biomass burning influence increased the abundance of soot and organic particles in the submicron fraction from 12% at low to 59% and 68% at moderate and high smoke levels, respectively. Smoke micromarkers of local biomass burning source emissions determined the microstructure of ambient aerosols representative for northern Southeast Asia.

A lack of understanding about the impact of Siberian wildfire emissions on the environment necessitates the characterization of biomass burning aerosol hygroscopicity. Flaming fires of typical Siberian biomass (pine and debris) were simulated during small-scale combustion experiments in a Large Aerosol Chamber (LAC). Analyses of individual particles with respect to morphology and elemental composition allows the separation of freshly-produced smoke into five fractions with the elemental carbon, chain soot agglomerates, irregular internally mixed soot, and distinct irregular minerals of fly ash containing S, Ca, Al, and Si. Aging in a dark chamber leads to an appearance of the fraction with inorganic inclusions such as KCl and CaCl2. Categorization of fresh-emitted and aged particles on hydrophobic, hydrophilic, and hygroscopic ones is performed. The criteria for categorization are extended from fossil fuel high-temperature combustion, based on a concept of water uptake by soot particles and utilization of a number of reference soots with known oxygen content and mixtures with sulfates and other inorganic salts. We show how the hydration properties of emitted smoke particles and inorganic inclusions can increase the initial level of smoke hygroscopicity.

The complexity and large variability of transport-emitted aerosols leads to necessity of comprehensive characterization of their physico-chemical and toxicological properties, remaining great uncertainties in health effect assessments. Particles produced by combustion of fossil diesel (B0), 20% rapeseed methyl ester in fossil diesel (B20), and pure rapeseed methyl ester (B100) were sampled from exhaust of an Opel Astra diesel engine using sulfated ash, phosphorous and sulfur (SAPS) lube oil with low and high ash content. Microscopic and chemical characterization is performed to quantify the common and specific properties of diesel/biodiesel exhausts. Hydrophobic saturated aliphatic dominate diesel particle chemistry. Oxygen and nitrogen-containing functionalities are specific for more hydrophilic biodiesel particles. A full range of chemical species for individual particles is grouped by clustering technique combined with water-soluble ion measurements. Analysis of group abundance shows carbonaceous particles (soot externally mixed with inorganic salts) and inorganic fly ash (metal oxides) in a structure of exhaust, in correlation with inorganic contaminations in fuel and lube oil. Quantification of particle types in terms of physicochemical relevance supports the identification of groups which may act as biomicromarkers discriminating between diesel and biofuel exhaust and micromarkers of using high ash lube oil, thus providing a basis for correlative toxicological assessment of diesel/biofuel engine emissions.

The results of the effect of high-fluence irradiation (fluence ~3 × 1018 cm–2) with 30-keV C+ ions at a temperature of 250°C on the structure and surface morphology of polyacrylonitrile-based carbon fibers reinforcing the composite KUP-VM are presented and discussed. Scanning electron microscopy shows that the irradiation of carbon fibers with their own ions does not lead, as in the cases of irradiation with ions of inert gases and nitrogen, to corrugation of the fiber surface. The roughness of the composite surface remains comparable to the nonirradiated sample. According to Raman-spectroscopy data, irradiation with carbon ions at temperatures above that of dynamic annealing of radiation-induced damage leads to the formation of a disordered graphite-like layer, as in the cases of irradiation with inert-gas ions. The lack of corrugation of the carbon-fiber surface under irradiation with carbon ions is associated with the lack of a gradient of radiation-induced damage in the modified layer and a texture characteristic of a carbon-fiber shell based on polyacrylonitrile.

We perform submicron corrugation of the surface of nongraphitized (processing temperature 1400°C) and graphitized (processing temperature 2800°C) Zoltek PX35 polyacrylonitrile carbon fibers by high-fluence irradiation with nitrogen and argon ions with an energy of 30 keV. The microgeometry of the surfaces of nongraphitized and graphitized carbon fibers irradiated with nitrogen ions is characterized by the presence of corrugations with different periods and heights at the same inclination of their faces. The similarity and difference in the microstructure of the surface layer of carbon fiber after heat treatment and ion irradiation, observed by Raman spectroscopy data, are analyzed and discussed. The data obtained suggest an increase in the tensile strength of the modified carbon-fiber layer with a decrease in the elastic modulus. The reasons and conditions for the corrugation of carbon fibers during their ion irradiation are discussed.

The results of experimental study of the irradiation under 30 keV Ar+ with the temperature ∼250 °C of viscose based carbon cloth TGN-2MK and SU-2500 glassy carbon are presented. According to the scanning electron microscopy and Raman spectroscopy, modified layer of TGN-2MK obtained by ion irradiation is similar of modified layer of the glassy carbon in the structure and morphology. The formation of nanoscale wall in both cases occurs during graphitization under conditions of dynamic annealing of radiation damage.

The results of the atmospheric sea surface layer aerosol composition studies executed during expedition “Sever-2015” on the route from Arkhangelsk to the Severnaya Zemlya archipelago from October 9 to 26, 2015 are presented. The data about mass concentration of black carbon (EBC) obtained with high spatial-temporal resolution in the White, Barents and Kara Seas showed its signifi cant variability: from background values about 20 ng/m3 to values of more than 1000 ng/m3 during periods of air mass transfer from the continent. Cluster analysis of the microstructure of natural arctic aerosols gave possibility to identify the dominant groups of particles of sea salt and calcium sulfate. In case the increase of EBC up to 250 ng/m3 the groups of carbon-containing aerosols and particles rich in sulfur, characteristic for emissions from the combustion of natural fuel were revealed.

This is a comprehensive study of the physicochemical characterization of multicomponent aerosols in the smoky atmosphere of Moscow during the extreme wildfires of August 2010 and against the background atmosphere of August 2011. Thermal–optical analysis, liquid and ion chromatography, IR spectroscopy, and electron microscopy were used to determine the organic content (OC) and elemental content (EC) of carbon, organic/inorganic and ionic compounds, and biomass burning markers (anhydrosaccharides and the potassium ion) and study the morphology and elemental composition of individual particles. It has been shown that the fires are characterized by an increased OC/EC ratio and high concentrations of ammonium, potassium, and sulfate ions in correlation with an increased content of levoglucosan as a marker of biomass burning. The organic compounds containing carbonyl groups point to the process of photochemical aging and the formation of secondary organic aerosols in the urban atmosphere when aerosols are emitted from forest fires. A cluster analysis of individual particles has indicated that when the smokiest atmosphere is characterized by prevailing soot/tar ball particles, which are smoke-emission micromarkers.

A series of experiments aimed at studying the effect of combustion regimes of typical Siberian biomasses on the optical, microphysical, and physical-chemical properties of smoke aerosols was performed in the Large Aerosol Chambe, Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences. A comprehensive data analysis showed that temperature regime of Siberian pine and coniferous tree burning has a key effect on the formation and time dynamics of all smoke characteristics. The polarization spectronephelometer measurements of light scattering are used to determine the size distributions and absorption indices of particles. Particles in the smoldering phase are weakly absorbing, but the mixed phase contains a strongly absorbing fine component produced in open flame phases. We studied microstructure characteristics of aerosols by the analysis of morphology and elemental composition. Groups of soot and organic particles were determined as micromarkers of emissions in open flaming and smoldering phases, respectively. The organic and elemental carbon contents, origin and concentration of chemical compounds in the water-soluble ion fraction exhibit a strong dependence on the combustion phase. Sugar anhydride (levoglucosan) was determined in the smoldering phase as a stable molecular marker of Siberian pine burning. A number of specific markers of coniferous wood burning were identified among the chemical compounds. Smoke aging is accompanied by condensation of organic and inorganic compounds, transformation of aerosol surface chemistry, and the formation of the group of potassium-rich particles, all demonstrating the complexity and variability of the chemical composition and microstructure of atmospheric aerosol pollution during Siberian forest fires.

A new method of obtaining magnetic porous composite materials is described, which is based on the self-propagating high-temperature synthesis (SHS) in the form of solid-phase combustion. The SHS process involves transformation of the nonmagnetic α-Fe 2 O 3 particles (contained in the initial mixture) into magnetic Fe 3 O 4 particles. The synthesized material comprises a porous carbonaceous matrix with immobilized Fe 3 O 4 particles. The obtained composite has been characterized by electron microscopy, X-ray diffraction, Mössbauer spectroscopy, and magnetic measurements. The sorption capacity of the porous material has been studied.

The effects of CW laser radiation with a wavelength of lambda = 532 nm on ethyl methacrylate copolymer films doped with the Ag(hfac)COD silver precursor were studied. Laser heating of the polymer composite (up to 150-170 degrees C), induced by the formation of highly absorbing silver nanoparticles (NPs), brings about an accelerated photo-thermochemical decomposition of the precursor, plastification of the polymer, local transition of the composite matrix to a colloidal state and intense thermocapillary convection in the dynamic active colloid formed. As a result, a directed transport of silver NPs from the center of the laser beam to its periphery takes place, leading to the formation of a ring structure with a very high concentration of silver NPs.

Enhancement of biomass burning-related research is essential for the assessment of large-scale wildfires impact on pollution at regional and global scale. Starting since 6 August 2010 Moscow was covered with thick smoke of unusually high PM10 and BC concentrations, considerably affected by huge forest and peat fires around megacity. This work presents the first comprehensive physico-chemical characterization of aerosols during extreme smoke event in Moscow in August 2010. Sampling was performed in the Moscow center and suburb as well as one year later, in August 2011 during a period when no biomass burning was observed. Small-scale experimental fires of regional biomass were conducted in the Moscow region. Carbon content, functionalities of organic/inorganic compounds, tracers of biomass burning (anhydrosaccharides), ionic composition, and structure of smoke were analyzed by thermal-optical analysis, FTIR spectroscopy, liquid and ion chromatography, and electron microscopy. Carbonaceous aerosol in August 2010 was dominated by organic species with elemental carbon (EC) as minor component. High average OC/EC near 27.4 is found, comparable to smoke of regional biomass smoldering fire, and exceeded 3 times the value observed in August 2011. Organic functionalities of Moscow smoke aerosols were hydroxyl, aliphatic, aromatic, acid and non-acid carbonyl, and nitro compound groups, almost all of them indicate wildfires around city as the source of smoke. The ratio of levoglucosan (LG) to mannosan near 5 confirms the origin of smoke from coniferous forest fires around megacity. Low ratio of LG/OC near 0.8% indicates the degradation of major molecular tracer of biomass burning in urban environment. Total concentration of inorganic ions dominated by sulfates SO42− and ammonium NH4+ was found about 5 times higher during large-scale wildfires than in August 2011. Together with strong sulfate and ammonium absorbance in smoke aerosols, these observations prove the formation of secondary inorganic species associated with wildfire gaseous emissions and their transformation in aged smoke. Accumulation of carbonyl compounds during extreme smoke event in Moscow resulted from photochemical aging and secondary organic aerosol (SOA) formation in the urban atmosphere. The mixture of carbonaceous particles and dust revealed multicomponent structure of Moscow smoke aerosols, pointing the difference with non-smoke ambient aerosols. The abundance of group containing soot and tar balls approached at least a half of total aerosol concentration during extreme event, relating to elevated OC, EC and SOA. Fly ash groups contained calcium sulfates and carbonates from soil entrainment by hot air convection. Small-scale open fire experiments support the identification of specific chemical features of regional biomass burning and demonstrate the strong impact of large-scale wildfires on aerosol chemistry and air quality in highly polluted megacity.

Smoke aerosol emitted by large scale wildfires in the European part of Russia and Ukraine, was transported to Athens, Greece during August 2010 and detected at an urban background site. Measurements were conducted for physico-chemical characterization of the aged aerosol and included on-line monitoring of PM10 and carbonaceous particles mass concentrations, as well as number size distributions and aerosol optical properties. In addition TSP filter samples were analyzed for major inorganic ions, while morphology and composition of particles was studied by individual particle analysis. Results supported the long-range transport of smoke plumes from Ukraine and Russia burning areas indicated by back trajectory analysis. An increase of 50% and 40% on average in organic (OC) and elemental carbon (EC) concentrations respectively, and more than 95% in carbonate carbon (CC) levels was observed for the biomass burning (BB) transport period of August with respect to the previous month of July. Mean 24-h OC/EC ratio was found in the range 3.2-8.5. Single scattering albedo (SSA) was also increased, indicating abundance of light scattering constituents and/or shift of size distributions towards larger particles. Increase in particle size was further supported by a decreasing trend in absorption Angstrom exponent (AAE). Ion analysis showed major contribution of secondary species (ammonium sulfate and nitrate) and soil components (Ca2+, Mg2+). Non-sea salt K+ exhibited very good correlation with secondary species, indicating the long-range transport of BB smoke as a possible common source. Individual particle analysis of the samples collected during BB-transport event in Athens revealed elevated number of soot externally mixed with fly ash Ca-rich particles. This result is in agreement with the increased OC and CC levels measured, thus pointing towards the main components comprising the aged BB aerosol microstructure. (C) 2014 Elsevier Ltd. All rights reserved.

The paper describes formation conditions for and the structure of diamond-like materials films used in the manufacture of layered cold cathodes of emission electronics devices. The authors study the structure and field emission properties of layered structures with polycluster diamond and diamond-like carbon films (DCF) formed by various methods. It has been found that the best emission properties are characteristic of DCFs obtained by cathode sputtering. Emission from the surface of such films occurs on the boundaries of the globules.

The field emission (FE) of surfaces of highly oriented pyrolytic graphite (HOPG) UPV-1T and glassy carbon SU-2000 after irradiation with 30-keV Ar+ ions at different temperatures and incidence angles has been investigated. It has been found that irradiation of the (001) basal plane of UPV-1T at temperatures of T = 250 and 400°C results in the emergence of low-voltage FE with threshold values of the electric-field strength from 3 to 17 V/μm depending on the temperature and irradiation geometry. The lowest field-emission threshold is observed following irradiation at T ≈ 250°C and normal ion incidence. It is shown that ion irradiation of glassy carbon can also result in the low-voltage FE of its surface.