Material Damage Due to Electron Beam During Testing in the Environmental Scanning Electron Microscope (ESEM)

This study describes the development of cell-wall damage, i.e., the creation of cracks across or in the vicinity of pits during the testing of twenty microtomed spruce (Picea abies karst.) samples in the Environmental Scanning Electron Microscope (ESEM). Samples were investigated both in an unloaded condition and under a constant tensile load and at different moisture levels. Regions of the moisturecycled samples that had been exposed to an electron beam during image acquisition showed damage running through pits and their surroundings. Specimens loaded in the green condition and dried in the chamber for 2 h without beam exposure except during imaging showed no noticeable cell-wall damage. The results indicate that the electron beam may be a major source of damage initiation. Therefore, it is essential to note the circumstances of the test when explaining the observations made in ESEM studies

Creep behaviour of densified wood

Due to the reproducibility, good workability, suitable mechanical properties, and attractive aesthetic appearance, timber is widely used in the building industry. Among those properties, mechanical properties are important for the useability of timber in construction applications. It is well known that there is a positive relationship between wood density and its mechanical properties. That means the thermo-hydro-mechanical (THM) densification, i.e. transverse compression of the wood cells only by using additional temperature, moisture and mechanical action to increase its density without structural fracturing is a practicable method to increase the performance of low-density species and thereby improve its mechanical properties. The previous studies on wood densification mainly focused on the influence of process parameters on wood physical and mechanical properties and how to use post-treatment to reduce the set recovery. This study is in the field of increasing the use of densified timber in construction applications and thereby strengthen the competitiveness of wood as a construction material. In construction, however, densified timber normally needs to be exposed to long-term loading which may lead to creep deformation and reduction of load-bearing capacity. There is an obvious risk of reduced serviceability and safety of constructions containing densified wood. Studies of creep characteristics of densified wood are rare, and therefore the purpose of this study was to fill the gap in knowledge if the field of densified under bending load. Scots pine specimens subjected to THM densification, THM densification with a post-heat treatment, and THM densification combined with phenol resin impregnation were loaded under 3-point bending under the 35% of maximum stress level at 20℃ and 65% RH. Results from these tests will be presented.Finansiär: Republic of Slovenia</p

June versus March Calving for the Nebraska Sandhills: Economic Comparisons

Costs and returns of June and March calving systems were compared at four production phases. Financial costs of the June system were lowest, due primarily to lower costs of producing a weaned calf. Post-weaning financial and economic costs at each phase were nearly identical. Selling June-born steer calves at January weaning would double net returns compared to selling March-born steer calves at October weaning due to lower costs and higher market prices. Net returns for June-born steer calves retained beyond weaning are highest if calves are retained as yearlings and finished. Calves finished as calf-feds provided the highest net returns for the March calving system

CT-scanning of the drying process of Eucalyptus nitens

[EN] The drying of Eucalyptus nitens is a troublesome process as the species is extremely prone to drying defects. This paper reports ongoing research to improve the understanding of surface checking and cell collapse in Chilean grown Eucalyptus nitens during drying. Computed tomography (CT) scanning was used as a powerful tool for studying the internal changes in the wood-material during the drying process. Different levels of temperatures have been tested with the same equilibrium moisture content (EMC) conditions and low air velocity. The results confirm that a low drying temperature and a low air velocity, which results in a slow rate of drying, reduce internal cell collapse and surface checking .The project Eu-Trä: Innovativ Svenska teknik för tillverkning av chilenska eukalyptus till sågade trävaror (DNo. 2017-01524) is financed by the Eureka program (Vinnova, Sweden’s Innovation Agency) and is being carried out in collaboration with Alent Dynamic AB (Sweden) and TSST Energy LTDA (Chile).Couceiro, J.; Hansson, L.; Ambrož, A.; Sandberg, D. (2018). CT-scanning of the drying process of Eucalyptus nitens. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 1269-1276. https://doi.org/10.4995/IDS2018.2018.7380OCS1269127

Correlation of Studies between Colour, Structure and Mechanical Properties of Commercially Produced ThermoWood® Treated Norway Spruce and Scots Pine

The thermal modification of wood has become the most-commonly commercialised wood modification process globally, with the ThermoWood® process currently being the most dominant. As with all commercial processes, there is a need to have a robust quality control system, with several small–scale studies undertaken to date investigating quality control using a range of analytical methods, culminating in a multi-year assessment of colour as a means of quality control. This study, as an extension to this multi-year assessment, further explores the colour of Norway spruce and Scots pine commercially modified by the ThermoWood® S and D processes, respectively, along with the mechanical properties and structural characterisation by Fourier transform infrared (FT–IR) spectroscopy and principal component analysis (PCA) to ascertain further correlations between colour and other measurable properties. Infrared spectroscopy indicated modifications in the amorphous carbohydrates and lignin, whereas the use of PCA allowed for the differentiation between untreated and modified wood. Colour measurements indicated reduced brightness, and shifting toward red and yellow colours after thermal modification, hardness values decreased, whereas MOE and MOR values were similar for modified wood compared to unmodified ones. However, by combining the colour measurements and PC scores, it was possible to differentiate between the two modification processes (Thermo–S and Thermo–D). By combining the mechanical properties and PC scores, it was possible to differentiate the untreated wood from the modified ones, whereas by combining the mechanical properties and colour parameters, it was possible to differentiate between the three groups of studied samples. This demonstrates there is a degree of correlation between the test methods, adding further confidence to the postulation of using colour to ensure quality control of ThermoWood®

Dysregulated signaling, proliferation and apoptosis impact on the pathogenesis of TCRγδ+ T cell large granular lymphocyte leukemia

TCRγδ+ T-LGL leukemia is a rare form of chronic mature T cell disorders in elderly, which is generally characterized by a persisten

Metric-affine f(R) theories of gravity

General Relativity assumes that spacetime is fully described by the metric alone. An alternative is the so called Palatini formalism where the metric and the connections are taken as independent quantities. The metric-affine theory of gravity has attracted considerable attention recently, since it was shown that within this framework some cosmological models, based on some generalized gravitational actions, can account for the current accelerated expansion of the universe. However we think that metric-affine gravity deserves much more attention than that related to cosmological applications and so we consider here metric-affine gravity theories in which the gravitational action is a general function of the scalar curvature while the matter action is allowed to depend also on the connection which is not {\em a priori} symmetric. This general treatment will allow us to address several open issues such as: the relation between metric-affine $f(R)$ gravity and General Relativity (in vacuum as well as in the presence of matter), the implications of the dependence (or independence) of the matter action on the connections, the origin and role of torsion and the viability of the minimal-coupling principle.Comment: typos corrected, replaced to match published versio

Species-specific Typing of DNA Based on Palindrome Frequency Patterns

DNA in its natural, double-stranded form may contain palindromes, sequences which read the same from either side because they are identical to their reverse complement on the sister strand. Short palindromes are underrepresented in all kinds of genomes. The frequency distribution of short palindromes exhibits more than twice the inter-species variance of non-palindromic sequences, which renders palindromes optimally suited for the typing of DNA. Here, we show that based on palindrome frequency, DNA sequences can be discriminated to the level of species of origin. By plotting the ratios of actual occurrence to expectancy, we generate palindrome frequency patterns that allow to cluster different sequences of the same genome and to assign plasmids, and in some cases even viruses to their respective host genomes. This finding will be of use in the growing field of metagenomics