An environmental impact assessment of exported wood pellets from Canada to Europe

There have been increased interests on exporting wood pellets from Canada to Europe to meet the increased demand on biofuels in European countries. The wood pellet industry in Canada, especially in the west coastal region, has grown at an annual rate of more than 20% averaged over last 5 years due to the steady supply of wood residues. This paper attempted to analyze the fuel consumption and air emissions associated with the wood pellet production in British Columbia and export to Sweden based on a streamlined life cycle analysis, starting from tree harvesting for wood residue production to the shipping of wood pellets from Vancouver to Stockholm in Sweden. The results showed that about 7.2 GJ of energy is consumed for each tonne of wood pellets produced and shipped to Europe, representing about 39% of the total energy content of the wood pellets. Among those energies consumed over the life cycle, about 2.6 GJ is associated with long-distance ocean transportation. The ocean transportation is also the major contributor to environmental and health impacts, followed by the pellet production processes. The fossil fuel content, which quantifies the amount of fossil fuel consumed over the life cycle, for exported wood pellets ranged from 19% to 35%, depending on whether natural gas or wood residue is used in the drying operation during the wood pellet production stage. To reduce the fossil fuel content and the environmental impacts, wood residues should be used in the drying operation and, if possible, local market should be explored to reduce the energy consumption associated with wood pellet transportation over long distances.     

Persistent complex subliminal activation effects: First experimental observations.

A strong recent focus on unconscious processes has increased interest in subliminal stimulation and other experimental activation technologies. Five experiments using male and female university students (N = 365) were carried out to compare 5-ms exposures of "mommy and I" stimuli with 5-ms control stimulation. Measures of self-mother similarity and other variables taken 7-14 days after exposure were more strongly correlated among experimental participants. Such complex, persistent effects may follow when powerfully activating stimuli administered under wholly unconscious conditions provokes schematic processing of social information and behavioral confirmation. These scientifically exciting and ethically problematic findings imply a need for further reduction of the role accorded to conscious volition and control in psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adsorption of glyphosate on goethite (alpha-FeOOH): surface complexation modeling combining spectroscopic and adsorption data

N-(phosphonomethyl)glycine (glyphosate, PMG) is the most widely used herbicide, and its adsorption onto soil minerals plays a significant role in its mobility and rate of degradation. In this work, we present the results of the first serious effort to find a realistic surface complexation modelthatfits both adsorption and total proton concentration data for PMG on the common soil mineral, goethite. Special attention was focused on making sure that the final model was in good semiquantitative agreement with previously reported X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopic measurements. Electrostatic effects were accounted for using the Basic Stern model, and the charges of the PMG-containing surface complexes were assumed to be distributed across the 0- and beta-planes. The reactions for the protonation of the goethite surface were described using the 1 pK model. We optimized on the intrinsic formation constants and the charge distributions of the complexes, as well as the initial total proton concentration (I = 0.1 M Na(NO3), 25.0 degrees C), and the following model was obtained. triple bond FeOH(0.5-) + H3L <==> triple bond FeHL(1.5-) + H(+) + H2O Log10beta = 4.70 +/- 0.08, Q0 = -0.18 +/- 0.02 triple bond FeOH(0.5-) + H3L <==> FeL(2.5-) + 2H(+) + H2O Log10beta = -3.9 +/- 0.1, Q0 = -0.7 +/- 0.1 Here, beta is the intrinsic formation constant, Q0 is the charge at the 0-plane, and the errors are reported as one standard deviation. The charge distributions of the complexes are rationalized by considering intramolecular hydrogen bonding between the protons of the amine group and both the phosphonate and carboxylate groups.     

Demonstration-based learning and control for automatic grasping

We present a method for automatic grasp generation based on object shape primitives in a Programming by Demonstration framework. The system first recognizes the grasp performed by a demonstrator as well as the object it is applied on and then generates a suitable grasping strategy on the robot. We start by presenting how to model and learn grasps and map them to robot hands. We continue by performing dynamic simulation of the grasp execution with a focus on grasping objects whose pose is not perfectly known.     

An experimental and theoretical study of heat-affected zone austenite reformation in three duplex stainless steels

Three duplex grades, one molybdenum-free, one 22Cr type, and one super duplex grade, have been subjected to weld simulation treatments, and the resulting microstructures have been quantified by automatic image analysis techniques. Substantial differences between the duplex grades were observed with an increased ability to reform austenite with increased alloying content. A theoretical model has been applied, based upon the paraequilibrium concept elaborated by Hillert, and the paraequilibrium compositions of individual phases were calculated as a function of temperature using the THERMOCALC database. A model based on Cahns theory of grain boundary nucleated reactions has also been utilized to calculate the kinetics of the reaction. By using this model, the grain size effects could be included in the treatment. The results of the calculations were compared with experimental data, and the experimental results were reproduced using the same parameter set for the three materials, with the exception of the diffusion coefficient values which had to be adjusted. This adjustment has in a later study been verified experimentally. The results validate the model used and the physical relevance of using the paraequilibrium model. The appropriateness of a paraequilibrium approach is also supported by experimental evidence from weld metal compositions. It is shown that the nitrogen content of the alloys plays an important role, and a higher nitrogen content results in more efficient austenite reformation. This implies that the alloy nitrogen compositions should lie close to the upper specification limits for these materials and nitrogen losses should be avoided on welding since the material properties, both mechanical and corrosive, are strongly related to the austenite-ferrite phase ratio.     

Prediction of the nutritive value of forages by near infrared reflectance photometry

A filter-type near infrared photometer equipped with 19 filters was used to predict crude protein, in-vitro digestibility of organic matter, and in-vivo and from in-vitro predicted metabolisable energy in forages. The investigation was performed using pure species of grasses and legumes, grass/legume mixtures and grasses preserved by different methods. The need for specific calibrations is demonstrated. Results obtained using combinations of six filters selected during the calibration procedure were compared with those obtained using the six standard filters recommended for grain analysis. There were indications that selected filter combinations will only give accurate results if the composition of the test samples is very similar to that of the calibration samples, i.e. of the same species or family as the calibration samples. The correlation coefficient between manual methods and n.i.r. reflectance varied from 0.83 to 1.00 for crude protein, 0.48 to 0.91 for rumen digestible organic matter and 0.35 to 0.92 for metabolisable energy. When samples of grass silage were analysed using grass/legume mixtures for calibration of the equipment, the correlations were poor. Although the technique is satisfactory for determinating crude protein in forages utilised in practical farming, the need for specific calibrations when assessing in-vivo organic matter digestibility or in-vivo metabolisable energy renders it inferior to chemical/biological methods.     

Convective drying of an individual iron ore pellet – Analysis with CFD

The objective of this paper is to model convective drying of an individual iron ore pellet placed in a free stream of air with the aim to clarify the different stages of drying. A numerical model taking into account capillary flow of liquid moisture and internal vapor flow is developed and implemented in a commercial available software for Computational Fluid Dynamics where also the flow around the pellet is simulated, yielding heat- and mass transfer coefficients as a function of position. A real pellet is optically scanned for its geometry and simulations of the drying are compared to experiments with very good agreement. The result clearly shows four stages of drying; (i) evaporation of liquid moisture at the pellet surface, (ii) surface evaporation coexisting with internal drying as the surface is locally dry, (iii) internal evaporation with completely dry surface and (iv) internal evaporation at boiling temperatures. A moisture front moving towards the core of the pellet will start to develop at the second drying stage and the results show that the front will have a non-symmetrical form arising from the surrounding fluid flow.     

Catalytic and structural effects of W-substitution in M2 Mo-V-Te-oxide for propene ammoxidation

Substitution of W for the Mo in M2-type Mo-V-Te-oxide was investigated. XRD, FTIR, XANES, and HRTEM verified that the substitution is possible in the whole range up to complete replacement of Mo by W. Catalytic measurements for propene ammoxidation show that both the specific activity and the selectivity to acrylonitrile pass through a maximum with increase of the W-content of the catalyst. XRD analysis indicates that the catalytic results, in part, can be explained by a disordered distribution of Mo, W, and V among the octahedral sites in M2 giving better catalytic performance than a more ordered arrangement does. Moreover, SEM and HRTEM imaging show that with increasing W-content, the M2 crystals change from μm-sized elongated crystals to spherical crystals of nm-size, influencing the type of surfaces being exposed and consequently the catalytic properties. Among the catalysts investigated, a catalyst with the composition (Mo_0.3W_0.7)_1.9V_1.0Te_1.1O₁₀ is the most active and selective one, giving 80% selectivity to acrylonitrile.