The dependence on temperature of gas-phase photocatalytic oxidation of methyl tert-butyl ether and tert-butyl alcohol

The influence of temperature on the mechanism and kinetics of gas-phase photocatalytic oxidation (PCO) and thermal oxidation (TO) of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) over TiO₂ was studied in a continuous flow annular reactor. The reaction products of PCO of both substances included acetone, water, carbon dioxide and carbon monoxide. Volatile TO products of MTBE included 2-methyl-1-propene (2-MP), carbon monoxide, carbon dioxide and water; TBA decomposed to 2-MP and water. Thermal oxidation of MTBE became noticeable at 388 K, TBA started to decompose thermally at 393 K. Both PCO and TO fit well to the Langmuir–Hinshelwood (L–H) model for monomolecular reactions. The dependence of the kinetic constants on temperature was established in the form of an Arrhenius equation. The TiO₂ catalyst showed no deactivation at temperatures above 373 K but gradually lost its activity below 373 K.     

Modelling and simulation of a copper electrolysis cell group

The energy consumption of the copper electrolysis process is relatively high. Electrical disturbances – like contact failures and short circuits – even increase the energy consumption and also reduce the quality of copper produced. To better understand and improve the process, a computationally feasible and reliable model of copper electrolysis cell group is of great importance. In this paper a multiphysical FEM model of copper electrolysis cell group is presented. A number of simplifications are proposed to make the model computationally feasible.     

Estimation of quantile mixtures via L-moments and trimmed L-moments

Moments or cumulants have been traditionally used to characterize a probability distribution or an observed data set. Recently, L-moments and trimmed L-moments have been noticed as appealing alternatives to the conventional moments. This paper promotes the use of L-moments proposing new parametric families of distributions that can be estimated by the method of L-moments. The theoretical L-moments are defined by the quantile function i.e. the inverse of cumulative distribution function. An approach for constructing parametric families from quantile functions is presented. Because of the analogy to mixtures of densities, this class of parametric families is called quantile mixtures. The method of L-moments is a natural way to estimate the parameters of quantile mixtures. As an example, two parametric families are introduced: the normal-polynomial quantile mixture and the Cauchy-polynomial quantile mixture. The proposed quantile mixtures are applied to model monthly, weekly and daily returns of some major stock indexes.     

Integrated procurement of pulpwood and energy wood from early thinnings using whole-tree bundling

To increase the volume of energy wood and pulpwood harvested from early thinnings, their procurement costs will have to be significantly reduced. This can be done through the integration of pulpwood and energy wood procurement applying a newly-developed supply chain based on whole-tree bundling. In 2007, the first prototype of the bundle harvester capable of incorporating compaction into the cutting phase was launched. Cost savings, especially in primary and secondary transportation, can be achieved by increasing the load sizes by replacing undelimbed whole trees with bundles. The bundles can be hauled by a standard forwarder to the roadside storage area, from where they are transported by a standard timber truck to the pulp mill. Batches of bundles are then fed into a wood flow consisting of conventional delimbed pulpwood. Separation of the bundles into pulpwood and energy wood fractions does not take place until the wood reaches the debarking drum.In this feasibility study, the required productivity level of bundle harvesting (i.e., cutting and bundling) in Scots pine-dominated stands was assessed by comparing the total supply chain costs based on whole-tree bundling with those of the other pulpwood and energy wood supply chains by means of system analysis. The cost calculations indicated that whole-tree bundling enables the procurement costs to be reduced to below the current cost level of separate pulpwood and energy wood procurement in early thinnings. The greatest cost-saving potential lies in small-diameter (d_1.3 = 7-10 cm) first-thinning stands, which are currently unprofitable for conventional pulpwood procurement.     

An electronic future in the Finnish Patent Office

Initially, the article describes how the Finnish Government has developed telecommunications and Internet use by launching initiatives, such as electronic identity cards for Finnish citizens to enable clear authentication for e-commerce. In addition, Finnish law for e-commerce in the public administration already provides the legal basis for filing, e.g. patent applications, electronically. Against this backdrop, the article describes the way in which the Finnish Patent Office is moving forward rapidly in the provision of services on the Internet. These include both statutory and legal filing and like actions, as well as, in cooperation with the EPO, the dissemination of patent information. On patent information, the plans to make all Finnish patents and the corresponding legal status accessible through the Internet, to expand the patent information centres and to heighten public awareness, are outlined.     

Potential of Long Non-Coding RNAs in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of visual impairment in the aging population with poorly known pathogenesis and lack of effective treatment. Age and family history are the strongest AMD risk factors, and several loci were identified to contribute to AMD. Recently, also the epigenetic profile was associated with AMD, and some long non-coding RNAs (lncRNAs) were shown to involve in AMD pathogenesis. The Vax2os1/2 (ventral anterior homeobox 2 opposite strand isoform 1) lncRNAs may modulate the balance between pro- and anti-angiogenic factors in the eye contributing to wet AMD. The stress-induced dedifferentiation of retinal pigment epithelium cells can be inhibited by the ZNF503-AS1 (zinc finger protein 503 antisense RNA 2) and LINC00167 lncRNAs. Overexpression of the PWRN2 (Prader-Willi region non-protein-coding RNA 2) lncRNA aggravated RPE cells apoptosis and mitochondrial impairment induced by oxidative stress. Several other lncRNAs were reported to exert protective or detrimental effects in AMD. However, many studies are limited to an association between lncRNA and AMD in patients or model systems with bioinformatics. Therefore, further works on lncRNAs in AMD are rational, and they should be enriched with mechanistic and clinical studies to validate conclusions obtained in high-throughput in vitro research.     

Transformation of self-assembled InAs/InP quantum dots into quantum rings without capping

Transformation of self-assembled InAs quantum dots (QDs) on InP(100) into quantum rings (QRs) is studied. In contrast to the typical approach to III--V semiconductor QR growth, the QDs are not capped to form rings. Atomic force micrographs reveal a drastic change from InAs QDs into rings after a growth interruption in tertiarybutylphosphine ambient. Strain energy relief in the InAs QD is discussed and a mechanism for dot-to-ring transformation by As/P exchange reactions is proposed.     

Estimating materials parameters in thin-film BAW resonators using measured dispersion curves

The dispersion curves of Lamb-wave modes propagating along a multilayer structure are important for the operation of thin-film bulk acoustic wave (BAW) devices. For instance, the behavior of the side resonances that may contaminate the electrical response of a thin-film BAW resonator depends on the dispersion relation of the layer stack. Because the dispersion behavior depends on the materials parameters (and thicknesses) of the layers in the structure, measurement of the dispersion curves provides a tool for determining the materials parameters of thin films. We have determined the dispersion curves for a multilayer structure through measuring the mechanical displacement profiles over the top electrode of a thin-film BAW resonator at several frequencies using a homodyne Michelson laser interferometer. The layer thicknesses are obtained using scanning electron microscope (SEM) measurements. In the numerical computation of the dispersion curves, the piezoelectricity and full anisotropy of the materials are taken into account. The materials parameters of the piezoelectric layer are determined through fitting the measured and computed dispersion curves.     

Engineering the substrate specificity of xylose isomerase

Xylose isomerase (XI) catalyzes the isomerization and epimerization of hexoses, pentoses and tetroses. In order to clarify the reasons for the low reaction efficiency of a pentose sugar, L-arabinose, we determined the crystal structure of Streptomyces rubiginosus XI complexed with L-arabinose. The crystal structure revealed that, when compared with D-xylose and D-glucose, L-arabinose binds to the active site in a partially different position, in which the ligand has difficulties in binding the catalytic metal M2. Lys183 has been thought to stabilize the open substrate conformation by hydrogen bonding to oxygen O1. Our results with L-arabinose showed that the substrate stays in a linear form even without a hydrogen bond between Lys183 and oxygen O1. We engineered mutations to the active site of Actinoplanes missouriensis XI to improve the reaction efficiency with L-arabinose. The mutation F26W was intended to shift the position of oxygen O1 of L-arabinose closer to the catalytic metal M2. This effect of F26W was modeled by free energy perturbation simulations. In line with this, F26W increased 2-fold the catalytic efficiency of XI with L-arabinose; the increase was seen mainly in kcat. The mutation Q256D was outside the sphere of the catalytic residues and probably modified the electrostatic properties of the active site. It improved 3-fold the catalytic efficiency of XI with L-arabinose; this increase was seen in both Km and kcat. This study showed that it is possible to engineer the substrate specificity of XI.     

Development of polyester and polyamide conductive fibre

Conducting polyester PET and polyamide PA-6 fibre and fabrics were prepared by in-situ chemical oxidative polymerisation using super critical fluid assisted process. The fibre materials and cloths produced were characterized by means of FTIR, WAXD, SEM, and DSC and two-probe resistivity. The samples were studied also by means of washing them several times. Homogeneous treated fibre materials with sustainable properties were produced. Melt spun fibre material of inherently conducting polymer blends have been reported earlier. Reasonable mechanical and electrical properties (resistance of 10⁵…10⁷ Ω/cm) are typical for blend of polypropylene and polyaniline. With bi-component extrusion technology the fibre as good as 10³…10⁵ Ω/cm is reachable.