Effects of climate change on biomass production and substitution in north-central Sweden

In this study we estimate the effects of climate change on forest production in north-central Sweden, as well as the potential climate change mitigation feedback effects of the resulting increased carbon stock and forest product use. Our results show that an average regional temperature rise of 4 °C over the next 100 years may increase annual forest production by 33% and potential annual harvest by 32%, compared to a reference case without climate change. This increased biomass production, if used to substitute fossil fuels and energy-intensive materials, can result in a significant net carbon emission reduction. We find that carbon stock in forest biomass, forest soils, and wood products also increase, but this effect is less significant than biomass substitution. A total net reduction in carbon emissions of up to 104 Tg of carbon can occur over 100 years, depending on harvest level and reference fossil fuel.     

Molecularly imprinted polymer coatings for open-tubular capillary electrochromatography prepared by surface initiation

Molecularly imprinted polymer coatings were synthesized in fused-silica capillary columns by the use of a surface-coupled radical initiator. The coatings were prepared using either toluene, dichloromethane, or acetonitrile in the prepolymerization mixtures and were 0.15-2 microm thick as determined by scanning electron microscopy. Solvent-dependent differences in appearance were observed. All the molecularly imprinted polymer-based open-tubular capillary columns were able to separate the enantiomers of propranolol by means of electrochromatography. Electrochromatographic performance was found to be dependent on the type of solvent used during the synthesis.     

Fullerene functionalized polymers

Summary The recent synthesis and macroscopic isolation of C₆₀ (buckminsterfullerene) has stimulated interest in its properties and chemical reactivity. Fullerenes are known to be attacked by nucleophiles and it has been reported that they react with small amines. There is, however, no report on the reaction of fullerenes with polymeric amines. Fullerenes were found to add to amine containing flexible hydrocarbon polymers such as ethylene propylene terpolymer (EPDM-amine) to obtain novel C₆₀ functionalized polymers. These materials are soluble in common solvents. The reaction of the fullerene and polymer was followed by infra-red spectroscopy and viscosity measurements.     

Dynamic flow rates of granular particles

Flow rates (W) of powder and granules are usually measured by letting the particulate solid pass through a stationary orifice. This is not a physical duplication of the event in, for instance, a rotary tablet machine, where the dies move in relation to the powder bed. An apparatus is described by which dynamic flow rates (i.e. flow into a moving orifice) can be measured. These dynamic flow rates (W₂ g/sec) differ from static flow rates. They are subject to the same dependence on particle diameter, d, as static flow rate, i.e.: W₂ ? W_m = ? k(d ? d_m)^s, where “m” refers to maximum and k and s are constants. They also exhibit the same type dependence on orifice opening (P cm) as static flow rates, i.e.W₂ = qPⁿ, where q and n are constants. The values for _n are 3 – 3.25, which is somewhat higher than for static flow where n = 2.3 – 2.6.     

The mechanism of failure in bending of paperboard

The behaviour of paperboard beams subjected to pure bending is analysed and related to tensile and compression stress-strain behaviour. Since the compression strength is lower than the tensile strength, beam failure occurs in compression. However, beam failure does not occur when the ultimate strain in pure compression is reached in the surface fibres. A plastic yielding in compression, which gives good agreement between experimentally-determined and theoretically-calculated bending moments up to failure is therefore suggested. At failure, the elastic energy stored in the sample causes propagation of an interlaminar crack at the compression side, which is observed in scanning electron micrographs.     

Engaging in activities involving information technology: dimensions, modes, and flow

An engagement mode involves a subject (e.g., a user of information technology, or IT) who is engaged in an activity with an object in a certain manner (the mode). The purpose of this study is to develop a general model of engagement modes that may be used for understanding how IT-related activities are shaped by properties of the user and the IT object. A questionnaire involving items on IT engagement and the experience of flow was administered to 300 participants. The results supported an engagement mode (EM) model involving 5 different engagement modes (enjoying/acceptance, ambition/curiosity, avoidance/hesitation, frustration/ anxiety, and efficiency/productivity) characterized on 3 dimensions (evaluation of object, locus of control between subject and object, and intrinsic or extrinsic focus of motivation). The flow experience follows from a balance between enjoying/ acceptance and efficiency/productivity propelled by ambition/curiosity. The EM model could provide a platform for considering how IT users, IT applications, and IT environments should work together to yield both enjoyment and efficiency. Actual or potential applications of this research include designing IT training programs on different levels of specificity.     

Parameterization-free active contour models with topology control

We present a novel approach for representing and evolving deformable active contours by restricting the movement of the contour vertices to the grid lines of a uniform lattice. This restriction implicitly controls the (re)parameterization of the contour and hence makes it possible to employ parameterization-independent evolution rules. Moreover, the underlying uniform grid makes self-collision detection very efficient. Our contour model is also able to perform topology changes, but – more importantly – it can detect and handle self-collisions at subpixel precision. In applications where topology changes are not appropriate, we generate contours that touch themselves without any gaps or self-intersections.     

Quantifying unfrozen water in frozen soil by high-field 2H NMR

To understand wintertime controls of biogeochemical processes in high latitude soils it is essential to distinguish between direct temperature effects and the effects of changes in water availability mediated by freezing. Efforts to separate these controls are hampered by a lack of adequate methods to determine the proportion of unfrozen water. In this study we present a high-field 2H2O NMR method for quantifying unfrozen water content in frozen soil. The experimental material consisted of the humic layer of a boreal spruce forest soil mixed with varying proportions of quartz sand and humidified with deuterium-enriched water. The relative standard deviation of unfrozen water content (measured as NMR signal integral) was less than 2% for repeated measurements on a given sample and 3.5% among all samples, based on a total of 16 measurements. As compared to 1H NMR, this 2H NMR method was found to be superior for several reasons: it is less sensitive to field inhomogeneity and paramagnetic impurities, it gives a bigger line shape difference between the ice and liquid signal, it shows a sharper response to water fusion, and it excludes the possibility of hydrogen in the organic material interfering with the measurement.