Debarking and drying of downy birch (Betula pubescens) and Scots pine (Pinus sylvestris) fuelwood in conjunction with multi-tree harvesting

Fuelwood moisture content is an important parameter for small and medium-sized heating plants. Optimal storage location and good fuelwood storage maintenance promotes drying efficiency and ensures good fuelwood quality. The effective drying period is limited to spring and summer. It is known that partial debarking of wood will enhance drying and improve fuelwood quality.The aim of the study was to test strip debarking as a mean to speed up the drying rate and to lower moisture and bark contents. The prerequisite was that debarking had to be integrated into the processing phase of a single grip harvester. The changes made in the harvester head had to be simple, easily installed and inexpensive.The mechanical objective was solved by drilling holes into the delimbing knives and placing bolts through the knives. In this manner the bolt head would strip bark off the stems when fed through the delimbing knives. The qualitative goal was to see if debarking improved drying rate and if harvesting season and species played a role.The data was collected on non-frozen and frozen pine wood in spring 2005 and in winter 2006, and on non-frozen birch in spring 2007. The debarking results of the non-frozen pine were 3-6% of the total surface area for the normal harvester head and 7-9% for the modified harvester head. The results for frozen pine were correspondingly 1% and 2-2.5%. The debarking results of non-frozen birch were 5-6% and 5-8%. Both studies of pine show that the bolts in delimbing knives doubled the amount of bark removed. There was no significant difference in birch.The delimbed Scots pine fuelwood storages reached 30% moisture content on fresh weight basis during the first drying season at landing. This result was obtained independently of the rate of debarking or the harvesting season. Seasoning over the second summer lowered the moisture content of pine fuelwood by another 5% units to 25%. Birch reached 20% during the first season.     

Antimicrobial properties of 1‐monoacylglycerols prepared from undecanoic (C11:0) and undecenoic (C11:1) acid

Antimicrobial activity of monoacylglycerols (MAG) with odd number of carbons prepared from undecanoic (MAG C11:0) and undecenoic (MAG C11:1) was investigated. Data showed that both studied substances successfully inhibited Gram‐positive cocci (Staphylococcus aureus) and spore‐forming rods (Bacillus cereus). Gram‐negative bacteria were highly resistant against MAG C11:0 and showed considerable tolerance against MAG C11:1. Minimum inhibitory concentration (MIC) of MAG C11:1 was possible to determine for Escherichia coli only. Complete inhibition of three fungi genera (Alternaria, Cladosporium, Trichothecium) was achieved using MAG C11:1 with a concentration higher than 750 µg/mL. The growth of Aspergillus niger, Mucor racemosus, Phoma, Scopulariopsis, Trichoderma was significantly reduced. Generally, MAG C11:1 was more efficient than MAG C11:0 against all tested microorganisms. Due to a rich production of degradation enzymes, some fungi species surprisingly adapted their metabolism during growth and were even able to utilise tested MAG as a source of carbon. Practical applications: MAG composed of fatty acids with odd number of carbons in molecule are a promising group of substances applicable in food industry and cosmetics. They represent materials with broad spectrum of antimicrobial activity, especially against Gram‐positive bacteria. More efficient MAG C11:1 with a double bond in molecule can be recommended for reduction of S. aureus that cause food enterotoxicosis.     

Postpartum Weight Retention is Associated with Elevated Ratio of Oxidized LDL Lipids to HDL-Cholesterol

Oxidized LDL lipids (ox‐LDL) are associated with lifestyle diseases such as cardiovascular diseases, metabolic syndrome and type 2 diabetes. The present study investigated how postpartum weight retention effects on ox‐LDL and serum lipids. The study is a nested comparative research of a cluster‐randomized controlled trial, NELLI (lifestyle and counselling during pregnancy). During early pregnancy (8–12 weeks) and 1 year postpartum, 141 women participated in measurements for determining of plasma lipids: total cholesterol (T‐C), LDL‐cholesterol (LDL‐C), HDL‐cholesterol (HDL‐C), triacylglycerols (TAG) and ox‐LDL. Subjects were stratified into tertiles (weight loss, unaltered weight and weight gain groups) based on their weight change from baseline to follow‐up. Ox‐LDL was determined by baseline level of conjugated dienes in LDL lipids. Among the group of weight gainers, concentration of TAG reduced less (?0.14 vs. ?0.33, p = 0.002), HDL‐C reduced more (?0.31 vs. ?0.16, p = 0.003) and ox‐LDL/HDL‐C ratio increased (3.0 vs. ?0.2, p = 0.003) when compared to group of weight loss. Both T‐C and LDL‐C elevated more (0.14 vs. ?0.21, p = 0.008; 0.31 vs. 0.07, p = 0.015) and TAG and ox‐LDL reduced less (?0.33 vs. 0.20, p = 0.033; ?3.33 vs. ?0.68, p = 0.026) in unaltered weight group compared to weight loss group. The women who gained weight developed higher TAG and ox‐LDL/HDL‐C ratio as compared to those who lost weight. Postpartum weight retention of 3.4 kg or more is associated with atherogenic lipid profile.     

Moderate anisotropy in the electrical conductivity of bulk MWCNT/epoxy composites

Bulk aligned multi-walled carbon nanotube films and their epoxy composites were prepared and their DC and AC conductivity studied. Nanotube films of up to 2 mm thickness were grown by catalytic chemical vapor deposition. Composites of nanotubes were made by infiltrating the films with a commercial epoxy. DC electrical resistivities in the axial direction of as-grown and purified films were found to be ∼1.2 Ωmm and ∼3.4 Ωmm, respectively. For the transverse direction the resistivity values were higher only with a factor of ∼2. In the case of composites, anisotropy is more pronounced showing more than an order of magnitude higher resistivity in the transverse direction (∼71.4 Ωmm) as compared to the axial value (∼4.2 Ωmm). AC behavior of the films investigated between 1 MHz and 3 GHz shows the presence of inductive and capacitive components at frequencies above ∼100 MHz. The moderate anisotropy for both DC and AC electrical properties are explained on the basis of the films’ structure combined with percolation theory and equivalent circuit models.     

Electromagnetic field computation in semiconductor laser resonators

An electromagnetic method based on rigorous diffraction theory of gratings is applied to the analysis of fields in semiconductor laser cavities. The method is based on the Fourier modal method; it is fully rigorous for infinitely periodic resonators and highly accurate for single resonators when absorbing boundary conditions are applied. Fundamental-mode intracavity and near-field distributions are evaluated for some selected geometries, and resonance frequencies are predicted.     

Calculating the permeability of model paper coating structures comprising incongruent particle shapes and sizes

In this paper, the disciplines of experimental research and computational science are conjoined with an objective geared towards an improved understanding of permeability in porous coatings. Three packing structures were considered, each one comprising a distribution with particles of similar shape. Models were built to mimic the experimental structures and then used for computational fluid dynamics (CFD) simulations as well as statistical analyses. Calculations of permeability are reported to within one order of magnitude of the experimental equivalents. A correlation is found to exist between statistical pore space disorder and the variation of permeability within the same packing microstructure.     

Context-Aware telephony over WAP

In this paper we introduce a novel approach to sharing context in order to enhance the social quality of remote mobile communication. We provide an analysis of how people start a conversation in situations where they meet physically, especially looking at the influence of the situation. This is then compared to the way remote communication is initiated using mobile phones. The lack of knowledge about the situation at the other end leads to the initiation of calls which are not appropriate to that situation. The solution we propose is to exchange context information before initiating the call. We implemented this concept using the Wireless Application Protocol (WAP). The application Context-Call offers a phone interface that provides information about the receiver when setting up a call. Based on that information, the caller can then decide to place the call, to leave a message or to cancel the call. Privacy issues that arise from this technology are discussed also.