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In this study, spray pyrolysis; an aerosol processing technique was utilized to produce a mixed-phase copper on carbon (Cu/Cu

Development of thermal processes for selective recovery of Zn and other valuable elements from municipal solid waste incineration (MSWI) fly ash requires comprehensive knowledge of the impact of gas atmosphere on the volatile behaviour of the element constituents of the ash at different reaction temperatures. This study assesses the partitioning of 18 elements (Al, As, Bi, C, Ca, Cd, Cl, Cu, K, Mg, Na, P, Pb, S, Sb, Sn, Ti, and Zn) between condensed and gaseous phases during thermal treatment of MSWI fly ash in both oxidising gas and reducing gas atmospheres, at different temperatures spanning the range 200–1050 °C. The operating atmosphere had major impacts on the partitioning of the following elements: As, Bi, C, Cd, Cu, Na, Pb, S, Sb, Sn, and Zn. The partitioning of these elements cannot be accurately predicted over the full range of investigated operating conditions with global thermodynamic equilibrium calculations alone, i.e. without also considering chemical kinetics and mass transfer. In oxidising conditions, the following elements were predominately retained in condensed phases, even at high temperatures: As, Bi, Sb, Sn, and Zn. All these elements, except As, were largely released to the gas phase (>70%) at high temperatures in reducing conditions. The impact of gas atmosphere on the volatility of Cd and Pb was greatest at low reaction temperatures (below ~750 °C). Results for volatile matrix elements, specifically C, Cl, K, Na, and S, are interpreted in terms of the mechanisms governing the release of these elements to the gas phase.

Nanomaterials (NM) exhibit novel physicochemical properties that determine their interaction with biological substrates and processes. Recent nano-technological advances are leading to wide usage of metallic nanoparticles (NPs) in various fields. However, the increasing use of NPs has led to their release into environment and the toxicity of NPs on human health has become a concern. Moreover, there are inadvertently generated metallic NPs which are formed during various human activities (e.g. metal processing and energy production). Unfortunately, there are still widespread controversies and ambiguities with respect to the toxic effects and mechanisms of metallic NPs, e.g. metal oxides including ZnO. In this study, we generated zinc containing NMs, and studied them in vitro. Different nano-sized particles containing Zn were compared in in vitro study to elucidate the physicochemical characteristics (e.g. chemical composition, solubility, shape and size of the particles) that determine cellular toxicity. Zn induced toxicity in macrophage cell line (RAW 264.7) was detected, leading to the cell cycle disruption, cell death and excitation of release of inflammatory mediators. The solubility and the size of Zn compounds had a major role in the induced toxic responses. The soluble particles reduced the cell viability, whereas the less soluble NPs significantly increased inflammation. Moreover, uptake of large ZnO NPs inside the cells was likely to play a key role in the detected cell cycle arrest., final draft, peerReviewed

Fly and bottom ashes are collected at power plants to reduce the environmental effects of energy production. However, handling the ashes causes health problems for operators, maintenance workers and truck drivers at the power plants. Hence, we evaluated ash loaders’ peak inhalation exposures to the chemical components of ash and diesel exhausts in open and closed ash loading stations at biomass-fuelled combined heat and power plants. We also carried out chemical and morphological analyses of the ashes to evaluate their health hazard potential in order to find practical technical measures to reduce workers’ exposure. On the basis of X-ray diffraction analyses, the main respirable crystalline ash compounds were SiO2, CaSO4, CaO, Ca2Al2SiO7, NaCl and Ca3Al2O6 in the fly ashes and SiO2, KAlSi3O8, NaAlSi3O8 and Ca2Al2SiO7 in the bottom ashes. The short-term exposure levels of respirable crystalline silica, inhalable inorganic dust, Cr, Mn, Ni and nitric oxide exceeded their Finnish eight hours occupational exposure limit values in the closed ash loading station. According to our observations, more attention should be paid to the ash-moistening process, the use of tank trucks instead of open cassette flatbed trucks, and the sealing of the loading line from the silo to the truck which would prevent spreading the ash into the air. The idling time of diesel trucks should also be limited, and ash loading stations should be equipped with exhaust gas ventilators. If working conditions make it impossible to keep to the OEL values, workers must use respirators and protect their eyes and skin., final draft, peerReviewed

Defect spinel phase lithium titanate (Li 4 Ti 5 O 12 ) has been suggested as a promising negative electrode material for next generation lithium ion batteries. Flame spray pyrolysis has been shown to be a viable fast, one-step process for synthesis of nanoparticulate Li 4 Ti 5 O 12 . However, due to the rapid quenching that is integral to the process the crystallite size remain very small and non-uniform. To overcome this shortcoming a vertical flow tube furnace was used to increase the high-temperature residence time. This resulted in an increase in the crystallite size and crystallinity of the product. As a result of this increase the electrochemical performance of the Li 4 Ti 5 O 12 was markedly improved. Furthermore, silver doping of the Li 4 Ti 5 O 12 material can be carried out simultaneously with its synthesis in the FSP process. The resulting nanosized silver particles on the surface of the Li 4 Ti 5 O 12 particles further improve the electrochemical performance during high current operations. The specific capacities of these high-temperature synthesised pure and silver-doped Li 4 Ti 5 O 12 nanoparticles were found to increase by up to 6% and 19%, respectively, compared to a commercial reference. Thus the technique provides a simple method for synthesising superior quality Li 4 Ti 5 O 12 for battery applications.

Iron doped aluminium oxide nanoparticles are of interest for number of applications (e.g. water treatment, catalytic conversion of exhaust gases) due to their high surface area, hardness, catalytic and magnetic properties. In the present study, flame spray pyrolysis (FSP) was employed for the synthesis of Fe/Al2O3 nanoparticles. Precursor solutions of aluminium acetylacetonate (0.2 mol·L− 1) and ferrocene (0 to 0.2 mol·L− 1) in toluene were used to synthesise pure and iron (Fe) doped Al2O3. The particle composition and morphology were studied and effect of iron concentration was analysed. It was found that in the absence of the iron precursor, FSP produced a mixture of two Al2O3 polymorphs: θ-Al2O3 and η-Al2O3. The addition of ferrocene as an iron precursor was found to suppress formation of θ-Al2O3. At an iron molar concentration of 0.2 mol·L– 1 mainly hercynite, FeAl2O4, was observed. Furthermore, increasing the iron concentration caused a linear shift of the X-ray diffraction peaks from positions corresponding to η-Al2O3 to those of FeAl2O4. This indicates the formation of a solid solution (FexAl2O3 + x) at intermediated concentrations. It was also found that the primary particle size, which was below 10 nm, did not significantly change with the increased iron concentration and was comparable to the mean crystallite size indicating that size of these single crystalline primaries is determined by the synthesis process rather than the chemistry of the product. However, the hydrodynamic size was around 180 nm indicating that the particles are agglomerates in the water suspension. Additionally, zeta potential of the nanoparticles was found to decrease slightly with increasing iron content, though in all cases it was above 50 mV. Finally, the potential of synthesized nanoparticles was examined for the removal of fluoride because fluoride causes harmful health effects to human health at elevated concentrations. The results of fluoride removal using synthesized nanoparticles produced in this study showed that the highest fluoride removal efficiency was observed for the sample having no iron content.

There is currently great interest in replacing fossil-oil with renewable fuels in energy production. Fast pyrolysis bio-oil (FPBO) made of lignocellulosic biomass is one such alternative to replace fossil oil, such as heavy fuel oil (HFO), in energy boilers. However, it is not known how this fuel change will alter the quantity and quality of emissions affecting human health. In this work, particulate emissions from a real-scale commercially operated FPBO boiler plant are characterized, including extensive physico-chemical and toxicological analyses. These are then compared to emission characteristics of heavy fuel-oil and wood fired boilers. Finally, the effects of the fuel choice on the emissions, their potential health effects and the requirements for flue gas cleaning in small-to medium-sized boiler units are discussed. The total suspended particulate matter and fine particulate matter (PM1) concentrations in FPBO boiler flue gases before filtration were higher than in HFO boilers and lower or on a level similar to wood-fired grate boilers. FPBO particles consisted mainly of ash species and contained less polycyclic aromatic hydrocarbons (PAH) and heavy metals than had previously been measured from HFO combustion. This feature was clearly reflected in the toxicological properties of FPBO particle emissions, which showed less acute toxicity effects on the cell line than HFO combustion particles. The electrostatic precipitator used in the boiler plant efficiently removed flue gas particles of all sizes. Only minor differences in the toxicological properties of particles upstream and downstream of the electrostatic precipitator were observed, when the same particulate mass from both situations was given to the cells.

The emissions and ash behaviour during combustion of wood chips, or co-combustion of two solid agricultural fuels (reed canary grass and barley straw) with wood chips, were studied. In addition, the sensitivity of the results towards different air-staging conditions was investigated using pure wood chips. The experiments were carried out in a 40-kW combustion reactor equipped with a reciprocating-grate burner. The addition of the reed canary grass to the wood chips increased only slightly the emission of fine particles (PM1), nitrogen oxides (NOX) and sulphur dioxide (SO2); while carbon monoxide (CO), hydrogen chloride (HCl), organic carbon (OC), elemental carbon (EC) and the geometric diameter (GMD) of the particles either decreased or remained unchanged. However, the number of particles emitted increased 2-fold in the reed canary grass combustion compared to the pure wood chips. In contrast, the addition of straw to wood chips substantially increased the emissions of PM1, CO, EC, SO2 and HCl. The straw-originating particles were mostly crystalline KCl, and their number emission was clearly reduced, but their size was larger compared to the case with pure wood chips. The distribution of the combustion air had only a very minor influence on the release of the major ash species, whereas the effect was significant for the release of specific trace metals and the products of incomplete combustion. Finally, the partitioning of ash-forming elements with various fuels was evaluated based on chemical analyses of the fuel, bottom ash and fine fly ash fractions.

Fine particles are the most important type of pollutant affecting urban air quality. Recent studies have highlighted the relevance for health effects of the zinc component of these particles. Zinc is traditionally associated with industrial and waste combustion plant emissions, although not covered by current regulations (e.g. the EU Waste Incineration Directive). However, pure wood combustion also produces substantial amounts of zinc particles. In this study, pure wood pellet fuels doped with three doses of Zn powder were combusted in a small grate boiler. The emissions were then analysed by a broad array of techniques to shed light on the health-related properties of particles originating from Zn-rich fuel combustion. In addition, reference pellets without Zn doping (during efficient and poor combustion conditions) were studied. Zinc was found to be efficiently released from the fuel and enriched in the fine particle fraction, a trend supported also by thermodynamic equilibrium calculations. The enrichment was systematically observed as changes in the size, mass, chemical composition, and shape of the particles. The growth of the particles was mainly due to the coagulation and growth of the pure crystalline zinc oxide (ZnO) cores. With high Zn doping ZnO nanorods were clearly formed, whereas with a low Zn content in the fuel other ash-forming species defined the particle morphology better. The ZnO formation process was found to be thermodynamically similar to the production of engineered nanomaterials. This study suggests that more attention should be paid to the zinc content of biomass fuels with regards to emission legislation, for example when wood bark is utilised in energy production. This concern, in particular, the small and medium scale (below 1 MW) power plants as efficient particle removal techniques are generally utilised in large scale power plants.

A novel porous tube reactor that combines simultaneous reactions and continuous dilution in a single-stage gas-phase process was designed for nanoparticle synthesis. The design is based on the atmospheric pressure chemical vapor synthesis (APCVS) method. In comparison to the conventional hot wall chemical vapor synthesis reactor, the APCVS method offers an effective process for the synthesis of ultrafine metal particles with controlled oxidation. In this study, magnetic iron and maghemite were synthesized using iron pentacarbonyl as a precursor. Morphology, size, and magnetic properties of the synthesized nanoparticles were determined. The X-ray diffraction results show that the porous tube reactor produced nearly pure iron or maghemite nanoparticles with crystallite sizes of 24 and 29 nm, respectively. According to the scanning mobility particle sizer data, the geometric number mean diameter was 110 nm for iron and 150 nm for the maghemite agglomerates. The saturation magnetization value of iron was 150 emu/g and that of maghemite was 12 emu/g, measured with superconducting quantum interference device (SQUID) magnetometry. A computational fluid dynamics (CFD) simulation was used to model the temperature and flow fields and the decomposition of the precursor as well as the mixing of the precursor vapor and the reaction gas in the reactor. An in-house CFD model was used to predict the extent of nucleation, coagulation, sintering, and agglomeration of the iron nanoparticles. CFD simulations predicted a primary particle size of 36 nm and an agglomerate size of 134 nm for the iron nanoparticles, which agreed well with the experimental data.

The catalytic properties of Co-Al spinel nanoparticles prepared by liquid-feed flame spray pyrolysis (L-F FSP) were investigated in the glycerol conversion in gas phase in an atmosphere of hydrogen. Reduction at 1123¿K of the as-synthesized spinel nanoparticles induced the formation a new phase containing metallic cobalt species. Although, the reducibility of cobalt oxides is greatly decreased due to interaction with aluminium species, this strong interaction may prevent the aggregation of Co particles under the harsh reduction conditions. X-ray photoelectron spectroscopy (XPS) of the reduced spinel nanoparticles at 1123¿K revealed that the Co/Al atomic ratio has decreased to Co/Al¿=¿0.11, which may indicate a redistribution of the aluminum and cobalt species at the surface of the sample submitted to the reduction in a flow of hydrogen at 1123¿K. X-ray diffraction (XRD) and high resolution electron microscopy (HRTEM) also reinforced the formation of metallic cobalt species after reduction of cobalt from the spinel nanoparticles at 1123¿K. The main products obtained from the conversion of glycerol in the gas phase were hydroxyacetone, pyruvaldehyde, lactic acid and lactide. FSP ensured uniform dispersion of the active metal on a support material.

We used bottomside ground observations and topside sounding data from the Intercosmos-19 satellite to study a Travelling Ionospheric Disturbance (TID) that occurred in response to Large-Scale Internal Gravity Wave (LSIGW) propagation during a substorm on November 30, 1979. We built a global scheme for the wavelike ionospheric variations during this medium substorm (AEmax 800 nT). The area where the TID was observed looks like a wedge since it covers the nighttime hours at subauroral latitudes but contracts to a 02 h local sector at low latitudes. The ionospheric response is strongly asymmetric because the wedge area and the TID amplitude are larger in the winter hemisphere than in the summer hemisphere. Clear evidence was obtained indicating that the more powerful TID from the Northern (winter) hemisphere propagated across the equator into the low latitude Southern (summer) hemisphere. Intercosmos-19 observations show that the disturbance covers the entire thickness of the topside ionosphere, from hmF2 up to at least the 1000 km satellite altitude at post-midnight local times. F-layer lifting reached 200 km, Ne increases in the topside ionosphere by up to a factor of 1.9 and variations in NmF2 of both signs were observed. Assumptions are made concerning the reason for the IGW effect at high altitudes in the topside ionosphere. The relationship between TID parameters and source characteristics determined from a global network of magnetometers are studied. The role of the dayside cusp in the generation of the TID in the daytime ionosphere is discussed. The magnetospheric electric field effects are distinguished from IGW effects. Research Highlights The global scheme for the large-scale TID propagation during a substorm is built. TID covers the entire thickness of the topside ionosphere. The area where the TID is observed looks like a wedge directed to the equator. TID area and amplitude are larger in the winter hemisphere than in the summer hemisphere. The more powerful TID from the winter hemisphere propagates into the summer hemisphere. Keywords: Substorm; Topside ionosphere; Internal gravity wave; IGW; Travelling ionospheric disturbance; TID

Herein, we present an aerosol filtration method for the fabrication of carbon nanoflower (CNF) thin films. The method was based on generation, evaporation and filtration of solvent encapsulated CNF droplets. The particles were collected on polytetrafluoroethylene membranes and roll-transferred at room temperature onto flexible polyethylene terephthalate substrates. Suspensions for spraying were made in low vapor pressure mixtures of EtOH/Hex (50/50 v/v%). Doping of starter suspensions was made by the addition of organometallic 1-dodecanethiol-coated gold nanoparticles (AuNPs). The produced films displayed substrate surface coverage of up to 83.3% ± 13.9% and a film thickness of up to 2.4 μm. The deposition of doped suspensions resulted in uniform distribution of AuNPs in the volume of the CNF film, which enables film application for flexible photovoltaics.

Variations in the dayside ionosphere parameters as a result of a large-scale acoustic gravity wave (LS AGW) were studied for the 17 February 1998 substorm using the super dual auroral radar network (SuperDARN) measurements. This event was characterised by a sharp rise in the AE index with a maximum of similar to 900 nT. The source of the disturbance responsible for the LS AGW appears to have been located within the plasma convection throat and in the dayside cusp region. The location of the source was obtained from studies of a number of datasets including high-latitude convection maps, data from 4 DMSP satellites and networks of ground-based magnetometers. The propagation of the IS AGWs caused quasi-periodic variations in the skip distance (with an amplitude up to 220-260 km) of the ground backscatter measured by up to 6 SuperDARN radars, including Goose Bay and Kapuskasing, resulting in two large-scale travelling ionospheric disturbances (LS TIDs). The IS TIDs had wave periods of 1.5 and 2 h, a velocity of similar to 400 m/s for both, and wavelengths of 2200 and 2900 km, respectively. These quasi-periodic variations were also present in the peak electron density and height of the F2 layer measured by the Goose Bay ionosonde. The numerical simulation of the inverse problem show good agreement between Goose Bay radar and Goose Bay ionosonde measurements. But these LS TIDs would be difficult to deduce from the ground based ionospheric station data alone, because h(m)F2 variations were 10-40 km only and f(o)F2 variations between 10% and 20%. The results demonstrate how important SuperDARN radars can be, and that this is a more powerful technique than routine ground-based sounding for studies of weak quasi-periodic variations in the dayside subauroral ionosphere related to LS AGW.

The Super Dual Auroral Radar Network (SuperDARN) network of HF coherent backscatter radars form a unique global diagnostic of large-scale ionospheric and magnetospheric dynamics in the Northern and Southern Hemispheres. Currently the ground projections of the HF radar returns are routinely determined by a simple rangefinding algorithm, which takes no account of the prevailing, or indeed the average, HF propagation conditions. This is in spite of the fact that both direct E- and F-region backscatter and 1½-hop E- and F-region backscatter are commonly used in geophysical interpretation of the data. In a companion paper, Chisham et al. (2008) have suggested a new virtual height model for SuperDARN, based on average measured propagation paths. Over shorter propagation paths the existing rangefinding algorithm is adequate, but mapping errors become significant for longer paths where the roundness of the Earth becomes important, and a correct assumption of virtual height becomes more difficult. The SuperDARN radar at Hankasalmi has a propagation path to high power HF ionospheric modification facilities at both Tromsø on a ½-hop path and SPEAR on a 1½-hop path. The SuperDARN radar at Þykkvibǽr has propagation paths to both facilities over 1½-hop paths. These paths provide an opportunity to quantitatively test the available SuperDARN virtual height models. It is also possible to use HF radar backscatter which has been artificially induced by the ionospheric heaters as an accurate calibration point for the Hankasalmi elevation angle of arrival data, providing a range correction algorithm for the SuperDARN radars which directly uses elevation angle. These developments enable the accurate mappings of the SuperDARN electric field measurements which are required for the growing number of multi-instrument studies of the Earth's ionosphere and magnetosphere.

The global pattern of the ionospheric response to large-scale acoustic gravity waves (LS AGW) has been constructed on the basis of an analysis of the large data set available during the 22 March 1979, magnetic storm. Ground-based ionospheric measurements and in-situ satellite measurements from Cosmos-900 were used in this study together with the Joule heating distribution in the high-latitude ionosphere specifically taken at the maxima of two substorms. The characteristics of the reconstructed planetary pattern of the LS AGW have been analysed in detail. It has been established that the LS AGW effects in the ionosphere in terms of both universal and local time were determined by the pattern of high-latitude atmospheric heating, and that the wave front of the LS AGW during both substorms covered practically all local times, i.e. all longitudes. In addition, it was established that one of the sources of the LS AGW was the thermospheric heating in the day-side cusp region. The local time dependence of the amplitude of the AGW effect in both maximum height, hmF2, and critical frequency, fOF2, has been reconstructed for the mid-latitude F2 layer. The AGW effects were clearly separated from the electric field effects related to turnings of the interplanetary magnetic field (IMF) BZ. In the day-time, electric field effects prevailed over the AGW effects, but during the night-time the amplitudes of these two effects were comparable. In contrast to the common view, fOF2 variations after the AGW passage had a quasi-sinusoidal character both in the day-time and in the night-time. In the night-time ionosphere a high degree of symmetry was observed for the AGW effects in Northern and Southern hemispheres. During the day-time a significant asymmetry was observed in the American longitudinal sector which was related largely to the peculiarities of the heating pattern in the high-latitude ionospheres of the Northern and Southern hemispheres. These observations demonstrate the complexity of the response of the ionosphere at all latitudes to heating of the auroral region.

A multi-frequency experiment at thermospheric heights using skip observations (METSO) has been designed for the co-operative UK twin located auroral sounding system (CUTLASS) radars for studying travelling ionospheric disturbances (TIDs). This mode uses both frequency and azimuthal scanning to build a two-dimensional phase map of the wave field independently in the two fields of view. On February 21, 2004, a superposition of three disturbances was observed and their parameters have been determined by a two-dimensional least-squares fitting method. Two of the disturbances were found to be consistent with models of TIDs caused by acoustic gravity waves (AGWs) from a point source: a medium-scale Earth-reflected mode and a large-scale direct mode. The propagation directions of the third disturbance, on the other hand, were found to differ in the two fields of view in a way inconsistent with a single point source, but rather a longitudinally extended one. All the waves were found to originate north of the radars.

Polar CAMMICE MICS data of proton pitch angle distributions with energies of 31–80 keV for the period of 1997–1998 were analyzed to determine the locations where anisotropic pitch angle distributions (perpendicular flux dominating) change to isotropic distributions. We study this high-altitude isotropic distribution boundary (IDB) in terms of its location in L-shell and MLT. Statistical results showed that this boundary is located at lower L-shells on the nightside and at higher L-shells on the dayside with most distant location at dawn. With the increase of magnetic activity, the IDB positions shift towards lower L-shells at all MLT. The locations of IDBs were also determined for different storm phases. A superposed epoch analysis revealed that the L-shells of the IDBs move to lower L-shells with decreasing Dst and to higher L-shells during Dst recovery. We made a comparison between Polar measurements of IDB at high altitudes and DMSP measurements of b2i boundary at low altitudes selecting several events during which simultaneous observations in the same local time sector were available. The magnetic field mapping using the Tsyganenko T01 model with the observed solar wind input parameters showed that Polar and DMSP were placed on nearly the same field lines, which leads us to suggest that the Polar IDB and the b2i boundary at DMSP are related.

Gold nanoparticles (AuNPs) were prepared with the atmospheric-pressure aerosol-assisted synthesis at temperatures between 200 and 800 °C. A designed, air-stable homoleptic cluster (AuC2R)10 (R = 2,6-dimethyl-4-heptanol) was used as the precursor. In this process, the aerosol droplets acted like microreactors in which the AuNPs were formed within few seconds. A dramatic change of color from bright yellow to very dark red of the produced particles took place as the temperature increased. In addition, a clear transformation from droplet-like, spherical gold particle clusters to solid, irregular nanoclusters took place as temperature increased from 200 to 800 °C. A systematic investigation of the influence of the process conditions (e.g., solvent, temperature) on the powder characteristics, including the particle size, crystallinity, structure, and surface morphology, was carried out. The primary particle size was below 5 nm in all cases and no significant sintering took place even with the particles prepared at high temperatures. Furthermore, the produced gold nanoparticles were phase pure with crystallite sizes between 1.8 and 2.8 nm depending on the process conditions. A formation of large number of monodisperse, non-sintered Au nanoparticles from one single droplet in spray synthesis has not been reported before.

Nanostructured lithium iron phosphate is a promising alternative for the positive electrode of next generation Li-ion batteries. The cost of $$\hbox {LiFePO}_{4}$$ material can be reduced by employing alternative low-cost precursors. In this study, iron sulphate heptahydrate produced as a by-product of industrial processing was utilised in aerosol-assisted nanoparticle synthesis. Aqueous precursor solution droplets were heated to 800 $$^{\circ}$$ C in a laminar flow reactor to achieve formation of $$\hbox {LiFePO}_{4}$$ with crystallite and particle size of about 60 and 300 nm, respectively. High fraction of two polymorphs of $$\hbox {LiFePO}_{4}$$ was found in the product powder. The fraction of the olivine polymorph was found to increase under reducing reaction atmosphere, while greater abundance of the high-pressure polymorph was obtained with an iron rich precursor stoichiometry. Hence, it was shown that the low-cost precursors can be used in aerosol-assisted synthesis of $$\hbox {LiFePO}_{4},$$ and the product composition can be fine tuned to the requirements of the application by varying the process parameters.

Multiple studies show that particulate mass (PM) generated from incomplete wood combustion may induce adverse health issues in humans. Previous findings have shown that also the PM from efficient wood combustion may induce enhanced production of reactive oxygen species (ROS), inflammation, and cytotoxicity in vitro and in vivo. Underlying factors of these effects may be traced back to volatile inorganic transition metals, especially zinc, which can be enriched in the ultrafine fraction of biomass combustion particulate emission. In this study, nanoparticles composed of potassium, sulfur, and zinc, which are the major components forming inorganic fine PM, were synthesized and tested in vitro. In addition, in vitro toxicity of PM from efficient combustion of wood chips was compared with that of the synthesized particles. Cytotoxicity, cell cycle arrest, ROS generation, and tumor necrosis factor alpha release were related to zinc concentration in PM. Potassium sulfate and potassium carbonate did not induce toxic responses. In light of the provided data, it can be concluded that zinc, enriched in wood combustion emissions, caused the toxicity in all of the measured end points.

Annealing of silicon-carbon nanoparticles was performed in argon at atmospheric pressure to enable formation of silicon carbide nanomaterials and/or carbon structures. Three precursor powders with increasing crystallinity and annealing temperatures from 1,900 to 2,600 °C were used to gain information about the effect of precursor properties (e.g. amorphous vs. nanocrystalline, carbon content) and annealing temperature on the produced materials. Three structures were found after annealing, i.e. silicon carbide crystals, carbon sheets and spherical carbon particles. The produced SiC crystals consisted of several polytypes. Low annealing temperature and increasing crystallinity of the precursor promoted the formation of the 3C-SiC polytype. Raman analysis indicated the presence of single-layer, undoped graphene in the sheets. The spherical carbon particles consisted of curved carbon layers growing from the amorphous Si–C core and forming a ‘nanoflower’ with a diameter below 60 nm. To our knowledge, the formation of this kind of structures has not been reported previously. The core was visible in transmission electron microscopy analysis at the annealing temperature of 1,900 °C, decreased in size with increasing temperature and disappeared above an annealing temperature of 2,200 °C. With increasing crystallinity of the precursor material, fewer layers (~5 with the most crystalline precursor) were detected in the carbon nanoflowers. The method presented opens up the possibility to produce new carbon nanostructures whose properties can be controlled by changing the properties of the precursor material or by adjusting an annealing temperature.

Defect spinel phase lithium titanate (Li4Ti5O12) has been suggested as a promising negative electrode material for next generation lithium ion batteries. However, it suffers from low electrical conductivity. To overcome this problem conduction path length can be reduced by decreasing the primary particle size. Alternatively the bulk conductivity of Li4Ti5O12 can be increased by doping it with a conductive additive. In this paper a steady, single-step gas-phase technique for lithium titanate synthesis that combines both approaches is described. The process is used to produce doped Li4Ti5O12 nanoparticles with primary particle size of only 10 nm. The product is found to consist of single-crystalline nanoparticles with high phase and elemental purity. Two dopant materials are tested and found to behave very differently. The silver dopant forms a separate phase of nanometre-sized particles of metallic silver which agglomerate with Li4Ti5O12. The copper dopant, on the other hand, reacts with the lithium titanate to form a double spinel phase of Li 3 (Li 1−2𝑥�� Cu 3𝑥�� Ti 5−𝑥�� )O 12 ., ISRN Nanotechnology, 2011, ISSN:2090-6072

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