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Calcium (Ca) is a critical plant nutrient typically applied at the time of planting in intensive Eucalyptus plantations in South America. At two sites in Colombia, we examined (1) calcium source by comparing growth after application of 100 kg ha−1 elemental Ca as lime or as pelletized highly reactive calcium fertilizer (HRCF) compared to a no application control, and (2) Ca rate by applying 0, 100, 200, and 400 kg ha−1 elemental Ca as HRCF with the addition of nitrogen, phosphorus, potassium, sulfur, and boron (NPKSB). We assessed height, diameter, and volume after 12 and 24 months. There were no growth differences from Ca source at the 100 kg ha−1 rate. We found increased volume after 24 months at the “Popayan” site with 200 and 400 kg ha−1 Ca HRCF+NPKSB treatments (112 and 113 m3 ha−1, respectively) compared to control (92 m3 ha−1), a 22% increase. In contrast, volume did not differ after 24 months at the “Darien” site, ranging from 114 m3 ha−1 in the 0 kg ha−1 Ca HRCF+NPKSB treatment to 98 m3 ha−1 in the control. Differences in response are likely due to soil characteristics, such as organic matter, emphasizing the importance of identifying site-specific nutrient deficiencies.

The addition of inorganic filler material in medium density fiberboard (MDF) and the effect on material properties as a function of particle size was examined. Medium density fiberboard was manufactured in a laboratory scale environment to a target raw densityof 750 kgm-3. Wood fibers were replaced by using calcium carbonate at 3 and 10 wt.% using fillers with weighted median particle sizes of d50= 2.0 μm and d50= 30 μm, respectively. Urea formaldehyde resin was used as binder in all MDF. The influence of filler addition on the modulus of elasticity, bending and tensile strength, dimensional stability and liquid permeability was investigated. The results demonstrate the effect of filler content and its dependence on particle size. The addition of filler with d50= 30 μm does not have any influence on material properties up to a filler content of 10 wt.%. Using the finer filler with d50= 2.0 μm at 10 wt.% filler, the quantity significantly increases the water adsorption and swelling behavior and reduces the strength properties of the MDF.

The unprecedented coronavirus disease 2019 (COVID-19) pandemic is a solemn reminder of the need to accelerate pharmaceutical innovation. The desire for fast access to vaccines triggered discussion of unrestricted access to research findings with the hope of facilitating the drug discovery process to combat COVID-19. Increasingly, abolition of the patent system is being discussed in connection with the fight against the pandemic. This may accelerate discovery of and increase access to medicines. However, society's desire for immediate disclosure of research findings conflicts with the inventor's legitimate interest to protect his or her invention as well as the need to recover investments made to develop the drug. The call for immediate disclosure of research results contradicts the interest of the inventor, whose primary goal is to secure his intellectual property rights, usually by applying for patent protection. In Europe, where patent law is based on the principle of absolute novelty, disclosure of the results reduces novelty and prevents subsequent patenting. Consequently, patenting remains the top priority for pharmaceutical companies in Europe, while disclosure of the results is secondary. The following article looks critically at the idea of using the grace period in European patent law to reconcile the conflicting interests of society and inventors in times of pandemic. In this paper, we investigate whether the implementation of a grace period in European patent law like that known in the USA, Japan, or Korea benefits the disclosure of results and increases the flow of information, ultimately leading to the promotion of innovation and rapid drug discovery. This article questions whether the use of a grace period provides a sufficient incentive to the inventor for rapid disclosure.

Addition of mineral filler in the surface layer of three-layer particle board and its influence on material properties was studied as a function of filler content. Three-layer particle board with a...

The influence of inorganic mineral filler addition on the material properties of medium density fiberboard (MDF) was inves- tigated at varying densities. Fibreboards with 10, 20 and 30% fibers replaced by calcium carbonate weight basis (dry/dry) and with target densities of 550, 700 and 850 kgm−3, respectively, were manufactured in a laboratory scale environment. The fiberboards were prepared by adding the mineral filler in dry powder form to the wood fibers to which urea formaldehyde UF resin in liquid state had previously been added. The obtained fiber-filler furnish, with the filler distributed uniformly by sticking to the UF resin on the fibers, was then pressed into panel forms. The effect of inorganic filler on elastic and strength properties, thickness swelling, permeability, as well as formaldehyde and volatile organic compound (VOC) emissions was quantified. The results demonstrate that the addition of mineral filler to MDF up to levels of 10 wt.% only have a small effect, if at all, on the material properties. The addition of calcium carbonate, and the associated increase in pH, does not have any effect on the strength development in the cured MDF, even though the results clearly demonstrate the negative effect on the curing kinetics of urea formaldehyde (UF) resin. Likewise, thickness swelling and formaldehyde and volatile organic com- pounds (VOC’s) emissions are not affected by filler addition levels of up to 10 wt.%. However, exceeding this level leads to a significant decline in strength, which is believed to be caused mainly by a reduction in the number of fiber-to-fiber stress transfer points. Further, increased emissions in VOC’s are expected due to a combination of the catalytic effect of the calcium carbonate that causes a breakdown of fatty acids to VOC’s and also increased emission rates due to a higher permeability of the MDF with filler addition levels above 10 wt.%.

Calcium hydrogen phosphate dihydrate (DCPD) was evaluated for its potential as a mineral fire retardant (FR) for application in melamine-urea-formaldehyde (MUF)-bonded wood composites. The efficacy as FR was studied in melamine-urea-formaldehyde (MUF)-bonded three-layer particleboard as a function of addition quantities of 10-, 20- and 30¿wt%. Resistance to fire and mechanical properties were determined by measuring the self-extinguishing time after flame exposure and internal bond strength, respectively. Combustion behavior was examined on samples with 20¿wt% DCPD addition by performing cone calorimetry experiments. The efficacy of DCPD was evaluated by determining the heat release, total heat release rate, smoke production, and smoke production rate and compared to another promising mineral-based fire-retardant composition (FRC) based on hydroxyapatite (HA) with deliquescent salt and HA alone. The effect of FR on the curing behavior of MUF in relation to mechanical properties was determined through viscosity measurements of MUF with 10 wt% addition of FR. The results confirmed the fire-retardant characteristics of DCPD in wood composites, albeit at higher application rates when compared to the FRC, however with no negative impact on resin curing time or mechanical strength. Based on the demonstrated compatibility in MUF, DCPD is considered a promising mineral extender of other FRs for application in UF-based wood composites.

A flame-retardant composition (FRC) composed of a surface-treated calcium carbonate-based mineral, having high porosity and loaded with deliquescent calcium chloride, was assessed for its potential as a flame retardant. Two FRCs with 16% and 26% calcium chloride (dry solid) stored in the pore structure, respectively, were studied with respect to their ability to absorb and release free water, and their efficacy in melamine–urea–formaldehyde (MUF)-bonded wood composites was investigated. Water absorption capacity was determined by performing absorption tests at a temperature of 20 °C and relative humidity (RH) of 65% and 95%, and the water release behavior was studied by performing thermogravimetric analysis. The FRCs have the capacity to hold substantial amounts of water (up to 60 wt%), but still behave as a free-flowing powder. The influence of addition of 10 and 20 wt% FRC in wood composites on reaction to fire and strength properties was determined by measuring the self-extinguishing time after flame exposure and internal bond strength, respectively. These effects were evaluated by comparison with ground calcium carbonate (GCC) and commercially available nitrogen containing phosphorus-based fire retardant. Although the FRCs had a negative impact on internal bond strength, the results confirmed their flame-retardant potential and showed that 10–15% by weight of the flame retardant would be a good compromise, in terms of the trade-off between flame retardancy and mechanical properties. The synergistic effects of multiple flame retardancy reaction mechanisms due to the presence of inorganic minerals and a hygroscopic agent, CaCl2, are also discussed. The unique properties of the FRC, which allow to exploit the fire-retardant potential of CaCl2 while at the same time eliminating the risk associated with the emission of hydrogen chloride gas during combustion, are confirmed by the results of FTIR spectroscopic analyses of the flue gas.

The cultivation of Populus spp. on acid soils is difficult mainly due to low nutrient availability, limiting the distribution and use of this marketable tree species. In this paper we report the results of two experiments, in which a granulated highly reactive micronized calcium carbonate (CaCO) was tested at increasing levels to improve the effect of NPKS fertilization on poplar growth. Twin field and pot experiments were carried out in 2017 using two different poplar clones, both of which are often used in Italy. In addition to analysing the data from the two experiments separately, common patterns were evaluated using a mixed-effect model with CaCO level and fertilization as fixed effects, and the experiment type as random effect. Growth was assessed in terms of total height, diameter and biomass. Taken together, the results from the two experiments showed that fertilization led to enhanced growth of poplar, but this effect was stronger when soil conditions in terms of pH and exchangeable Ca were at a sufficiently high level. Available nutrient concentrations in the soil and foliar nutrient concentrations in the plant suggested co-limitation of poplar growth by N and Ca. In conclusion, the results of this study on one hand emphasize the importance of adapting the level of CaCO to the given soil conditions, and on the other hand ask for further studies addressing the relative importance of elevated pH and improved Ca nutrition.

This study examines the use of alkenyl succinic anhydride (ASA)-surface treated calcium carbonate as a functional mineral additive for application in wood fiber (WF)-reinforced PLA composites. The influence of addition quantity on the material properties of PLA composites with 40 wt% fiber reinforcement was examined at mineral addition levels of 10 wt%, 20 wt% and 30 wt%, respectively. The benefits of ASA surface-treated calcium carbonate over untreated mineral were exemplified by comparing the thermomechanical properties of PLA composites at an addition level of 10 wt%. The results demonstrate that the addition of ASA-treated calcium carbonate has distinctive advantages over untreated mineral, in terms of both processability and material properties. First, it enables better control of the process by reducing the flowability of the PLA matrix. Furthermore, it improves the fiber adhesion with the PLA, allowing for a substantial reduction of PLA content in the composite formulation while maintaining material properties.

Wood Science and Technology, 47 (2), ISSN:0043-7719, ISSN:1432-5225

Zunehmend wird versucht, Laubholz im Bauwesen einzusetzen, um grosere Mengen stofflich zu verwerten und gleichzeitig die im Vergleich zum Nadelholz verbesserten mechanischen Eigenschaften des Laubholzes konstruktiv zu nutzen. Fur die teilweise dazu erforderlichen Berechnungen der Verformung von Platten oder auch von Spannungen in Brettschichtholz (z. B. Vorausberechnung von eventuellen Delaminierungen oder der Alterung von Klebverbindungen) ist die Kenntnis der richtungsabhangigen Kennwerte des Holzes in den Hauptachsen langs, radial und tangential erforderlich. Dies betrifft die elastischen Kennwerte (E-Modul, Schubmodul, Querdehnzahl), die Festigkeiten (auf Zug, Druck, Biegung und Scherung) und auch die Kennwerte fur den Feuchte- und Warmetransport (Diffusionskoeffizient, Warmeleitfahigkeit). Fur alle Kennwerte ist zudem die Kenntnis der Abhangigkeit von der Holzfeuchte und der Zeit notwendig. Ausgewahlte Parameter fur die Richtungs- und Feuchteabhangigkeit bei Rotbuchenholz werden fur E-Modul, Schubmodul und Querdehnzahl sowie die Warmeleitfahigkeit und die Diffusionskonstante vorgestellt. Die Ergebnisse fassen an der ETH Zurich, Arbeitsgruppe Holzphysik, durchgefuhrte Arbeiten zur Thematik zusammen. The orthotropic behaviour of the physical-mechanical properties of European beech wood Hardwood is tried to be increasingly established in building industry in order to realise a larger material output and to take at once into account the structural advantage of the improved mechanical properties of hardwood in comparison to softwood. For the partially required calculations therefore of stress and strain in boards and glued-laminated timbers (for example prognosis of potential delamination and aging of glued joints), it is essential to know the directional specific values of wood in the directions longitudinal, radial and tangential. This concerns the elastic specific values (YOUNG's modulus, shear modulus, POISSON's ratio), the specific values of strength (tension, compression, bending, shear) and also these of mass and heat flux (diffusion coefficient, thermal conductivity). Additionally, it is necessary to know the dependencies from moisture and duration for all specific values. Selected parameters for European beech wood will be presented concerning the dependencies of YOUNG's modulus, shear modulus, POISSON's ratio, thermal conductivity and diffusion coefficient from direction and moisture. The results summarize investigations on this topic realised at the Wood Physics Group of ETH Zurich.

Holzforschung, 67 (4), ISSN:0018-3830, ISSN:1437-434X

The present study examines the three-dimensional hygric and mechanical behavior of oak wood. The moisture equilibrium state, characterized by the sorption isotherms, was obtained from measurements taken during adsorption and desorption cycles. Sorption behavior was analyzed with the Dent theory and compared considering the sorption direction (adsorption/desorption cycle). Sorption parameters were provided for possible numerical applications in hygric material models. The corresponding swelling and shrinkage behavior was examined and characterized by the moisture expansion parameters for all anatomical directions. Orthotropic mechanical material behavior was characterized by determining the elastic engineering (Young's moduli, shear moduli, and Poisson's ratios) and the bending, compressive and compressive shear strength material parameters. Influence of moisture content (MC) on the mechanical material properties was studied using Young's moduli, Poisson's ratios, and the investigated strength para...

This study is concerned with the viscoelastic behavior of wood. The time dependency of the orthotropic compliance for beech wood is investigated by performing tensile (Te) and compressive (Co) creep experiments in all wood's orthotropic directions. Time evolution of the creep strain in the axial and lateral directions is recorded using the digital image correlation technique, to determine the time dependent Young's moduli and the Poisson's ratios needed for the calculation of the diagonal and nondiagonal elements of the viscoelastic compliance matrix. The results of this study demonstrate the viscoelastic character of wood, revealing the significant time influence on the mechanical behavior. The unequal time dependency of the Young's moduli and the Poisson's ratios obtained for the individual directions highlights the orthotropic nature of the viscoelastic compliance. Differences between the time dependent behavior for the compliance determined in Te and Co further indicate that the viscoelastic behavior of wood depends on the loading modality. Supported by the unequal evolution of the Te and Co creep strain, the results suggest that the time dependent stress–strain relationship of wood is essentially different in Te and Co. Poisson's ratio values, which are shown to increase with time in Te and decrease in Co, demonstrated this fact. The substantially different time dependency of the nondiagonal elements of the compliance matrix further emphasizes the complexity of the viscoelastic character of wood. Visualized by the time evolution of the corresponding nondiagonal elements ratio, differences between the Te and Co viscoelastic behavior become particularly visible in the time dependency of the orthotropic compliance asymmetry.

Physical and mechanical properties of sycamore maple (Acer pseudoplatanus L.) were extensively investigated as basis for three-dimensional material modelling for structural simulations (e.g., with finite element method) based on this species. The physical properties of swelling, water absorption, water vapour resistance and thermal conductivity were tested and the mechanical properties of tensile, bending and compression strength and of Young’s modulus (static and dynamic) as well as of Poisson’s ratio, shear strength, shear modulus and fracture toughness were determined. The tests were carried out for most of the features depending on moisture content and also in all three anatomical main directions: longitudinal, radial and tangential.

Journal of Materials Science, 47 (16), ISSN:0022-2461, ISSN:1573-4803