Forestry practices increase mercury and methyl mercury output from boreal forest catchments

We observed significant increases in the runoff output of total mercury (TotHg) and methyl mercury (MeHg) from a small spruce forest catchment (0.071 km2) after clear-cutting and soil treatment. Here we show that forest regeneration practices may act as an important additional source of TotHg and MeHg to forest lakes. TotHg and MeHg in runoff from two small forested catchments were monitored during the period 1994 to 2001. In the autumn of 1997, one of the catchments was clear-cut Soil preparation (mounding) was carried out in the autumn of 1998 and replanting in the summer of 1999. During the 3 years after the silvicultural treatment, medians of monthly flow-weighted TotHg and MeHg concentrations (12.02 ng L(-1) and 0.35 ng L(-1), respectively) and output loads (0.80-0.97 g km(-2) a(-1) and 0.011-0.036 g km(-2) a(-1), respectively) increased significantly compared to the 3 years calibration period (8.13 ng L(-1) and 0.15 ng 1(-1); 2.0-5.3 g km(-2) a(-1) and 0.11-0.16 g km(-2) a(-1), respectively). These results indicate that clear-cutting and/or soil treatment significantly increases the mobility of TotHg and MeHg accumulated in forest soil and may thus be an important factor for the total input of Hg to boreal freshwater ecosystems.     

Aerosol analysis of residual and nanoparticle fractions from spray pyrolysis of poorly volatile precursors

The quality of aerosol‐produced nanopowders can be impaired by micron‐sized particles formed due to non‐uniform process conditions. Methods to evaluate the quality reliably and fast, preferably on‐line, are important at industrial scales. Here, aerosol analysis methods are used to determine the fractions of nanoparticles and micron‐sized residuals from poorly volatile precursors. This is accomplished using aerosol instruments to measure the number and mass size distributions of Liquid Flame Spray‐generated alumina and silver particles produced from metal nitrates dissolved in ethanol and 2‐ethylhexanoic acid (EHA). The addition of EHA had no effect on silver, whereas, 5% EHA concentration was enough to shift the alumina mass from the residuals to nanoparticles. The size‐resolved aerosol analysis proved to be an effective method for determining the product quality. Moreover, the used on‐line techniques alone can be used to evaluate the process output when producing nanopowders, reducing the need for tedious off‐line analyses. © 2016 American Institute of Chemical Engineers AIChE J, 63: 881–892, 2017     

Olfactory responses of the parasitoidDiaeretiella rapae (Hymenoptera: Aphidiidae) to odor of plants,aphids, and plant-aphid complexes

Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae) is a parasitoid of several aphid species, including the Russian wheat aphid (RWA),Diuraphis noxia (Mordvilko), and the cabbage aphid (CA).Brevicoryne brassicae (L.). The response of matedD. rapae females to odors from wheat, cabbage, and plant-host complexes was investigated using a four-choice olfactometer. Experienced parasitoids, but not inexperienced females, responded positively to odors of the wheat-RWA complex in a no-choice test. In choice tests, experienced parasitoids did not respond to odors of uninfested cabbage and wheat leaves, but did respond positively to aphid-infested plants and to aphids alone. The response ofD. rapae to the cabbage-CA complex and to CA alone was significantly greater than to the wheat-RWA complex and RWA alone, suggesting an innate odor preference for crucifer-feeding aphids.     

Coating of Silica and Titania Aerosol Nanoparticles by Silver Vapor Condensation

Silica and titania aerosol nanoparticles are coated with silver through a physical coating process. The silver is evaporated in a tubular furnace flow system and condensed on the ceramic carrier particles with diameters of approximately 100?nm. The temperature gradient in the furnace system is optimized in order to avoid homogeneous nucleation of the silver. The generated ceramic–silver composite nanoparticles are characterized with aerosol measurements and analytical transmission electron microscopy. Two completely different particle morphologies are clearly observed, silver-decoration and composite doublet, with amorphous silica and crystalline rutile titania as the carrier particles, respectively. The former morphology consists of multiple silver nanodots with diameters of 1–10?nm, while in the latter morphology the silver had formed a larger structure with a size comparable to that of the carrier particle. Different shapes are observed in these larger silver structures, such as triangular, rodlike, and hexagonal. Differences in the silver particle migration on the surface of the silica and titania particles is proposed to be the key factor resulting into the two distinct particle morphologies.

Copyright 2015 American Association for Aerosol Research     

The association between dental arch dimensions and occurrence of Finnish dental consonant misarticulations in cleft lip/palate children

The evaluation of cortical evoked potentials after stimulation of the vesicourethral junction shows accurate and reproducible results and offers an elegant technique for evaluation of the viscerosensory pathways in patients with lower urinary tract dysfunction. The results must be considered in context with the results of simultaneously investigated pudendal somatosensory evoked potentials and the clinical symptomatology. They are of great help (1) in differentiating between intraspinal and extraspinal lesions of the afferent pathways of the detrusor if the etiology is unknown, (2) in differentiating between neurogenic and myogenic damage to the urinary bladder, and (3) in selecting patients not suitable for intravesical electrotherapy for bladder rehabilitation.     

Ultrafast Processing of Hierarchical Nanotexture for a Transparent Superamphiphobic Coating with Extremely Low Roll‐Off Angle and High Impalement Pressure

Low roll‐off angle, high impalement pressure, and mechanical robustness are key requirements for super‐liquid‐repellent surfaces to realize their potential in applications ranging from gas exchange membranes to protective and self‐cleaning materials. Achieving these properties is still a challenge with superamphiphobic surfaces, which can repel both water and low‐surface‐tension liquids. In addition, fabrication procedures of superamphiphobic surfaces are typically slow and expensive. Here, by making use of liquid flame spray, a silicon dioxide–titanium dioxide nanostructured coating is fabricated at a high velocity up to 0.8 m s^?1. After fluorosilanization, the coating is superamphiphobic with excellent transparency and an extremely low roll‐off angle; 10 µL drops of n‐hexadecane roll off the surface at inclination angles even below 1°. Falling drops bounce off when impacting from a height of 50 cm, demonstrating the high impalement pressure of the coating. The extraordinary properties are due to a pronounced hierarchical nanotexture of the coating.     

Characteristics of nFOG,an aerosol-based wet thin film coating technique

An atmospheric pressure aerosol-based wet thin film coating technique called the nFOG is characterized and applied in polymer film coatings. In the nFOG, a fog of droplets is formed by two air-assist atomizers oriented toward each other inside a deposition chamber. The droplets settle gravitationally and deposit on a substrate, forming a wet film. In this study, the continuous deposition mode of the nFOG is explored. We determined the size distribution of water droplets inside the chamber in a wide side range of 0.1–100 µm and on the substrate using aerosol measurement instruments and optical microscopy, respectively. The droplet size distribution was found to be bimodal with droplets of approximately 30–50 µm contributing the most to the mass of the formed wet film. The complementary measurement methods allow us to estimate the role of different droplet deposition mechanisms. The obtained results suggest that the deposition velocity of the droplets is lower than the calculated terminal settling velocity, likely due to the flow fields inside the chamber. Furthermore, the mass flux of the droplets onto the substrate is determined to be in the order of 1 g/m³s, corresponding to a wet film growth rate of 1 µm/s. Finally, the nFOG technique is demonstrated by preparing polymer films with thicknesses in the range of approximately 0.1–20 µm.     

Compressibility of porous TiO2 nanoparticle coating on paperboard

Compressibility of liquid flame spray-deposited porous TiO₂ nanoparticle coating was studied on paperboard samples using a traditional calendering technique in which the paperboard is compressed between a metal and polymer roll. Surface superhydrophobicity is lost due to a smoothening effect when the number of successive calendering cycles is increased. Field emission scanning electron microscope surface and cross‒sectional images support the atomic force microscope roughness analysis that shows a significant compressibility of the deposited TiO₂ nanoparticle coating with decrease in the surface roughness and nanoscale porosity under external pressure.

PACS

61.46.-w; 68.08.Bc; 81.07.-b     

Delineation of forest/nonforest land use classes using nearest neighbor methods

The k-Nearest Neighbor (kNN) method of forest attribute estimation and mapping has become an integral part of national forest inventory methods in Finland in the last decade. This success of kNN method in facilitating multi-source inventory has encouraged trials of the method in the Great Lakes Region of the United States. Here we present results from applying the method to Landsat TM and ETM+ data and land cover data collected by the USDA Forest Service's Forest Inventory and Analysis (FIA) program. In 1999, the FIA program in the state of Minnesota moved to a new annual inventory design to reach its targeted full sampling intensity over a 5-year period. This inventory design also utilizes a new 4-subplot cluster plot configuration. Using this new plot design together with 1 year of field plot observations, the kNN classification of forest/nonforest/water achieved overall accuracies ranging from 87% to 91%. Our analysis revealed several important behavioral features associated with kNN classification using the new FIA sample plot design. Results demonstrate the simplicity and utility of using kNN to produce FIA defined forest/nonforest/water classifications.