This study builds on previous research into the surface modification of beech wood with polyethyleneimine (PEI) prior to finishing it with a waterborne coating. Poly(diallyldimethylammonium chloride) (PDADMAC) is introduced as an alternative cationic polyelectrolyte for the pretreatment of beech wood surfaces. Wood samples were treated with aqueous 1% PDADMAC solutions of low (LMW-8000 g mol-1) and high (HMW-100,000-200,000 g mol-1) molecular weights, with or without NaCl addition. The effects of the treatments on wood surface chemistry, wettability, surface energy, water absorption, coating penetration, coating adhesion strength, and surface roughness of coated wood were analysed using FTIR, fluorescence microscopy, SEM/EDS, and standardised tests commonly used in wood surface finishing. The results showed that polyelectrolyte pretreatment modified the surface properties of wood, reducing water absorption and surface roughness without significantly affecting coating adhesion strength. PDADMAC formed a more uniform surface layer of wood with limited coating penetration, and NaCl addition improved wood surface smoothness (reducing surface roughness parameters of coated wood by 23%-29%, in samples treated with PDADMAC LMW with 0.01 M NaCl). These findings confirm that cationic polyelectrolyte pretreatment enhances the compatibility and performance of waterborne coatings, offering an environmentally friendly approach to improving wood-waterborne coating interactions.

Lignin-based polyurethanes represent a promising strategy for developing more sustainable wood coatings by partially replacing fossil-derived polyols with renewable aromatic biopolymers. In this study, a polyurethane formulated with organosolv lignin (LPU) was synthesized and applied on two non-durable European wood species, Fagus sylvatica L. and Picea abies L., and compared with a commercial fossil-based polyurethane (CPU). Coated samples were evaluated for color stability, gloss evolution, wettability, adhesion, impact and scratch resistance, and biological durability. Accelerated ageing was performed under xenon-light irradiation, while decay resistance was assessed against Gloeophyllum trabeum and Trametes versicolor. Additional tests examined susceptibility to blue-stain fungi and surface morphology via SEM. LPU produced a matte film with intrinsically darker coloration but excellent chromatic stability and minimal gloss variation during ageing. Its initial hydrophobicity was higher on beech and comparable to CPU on spruce. Although CPU exhibited superior adhesion and slightly better mechanical resistance, LPU provided enhanced protection against blue-stain fungi—particularly on spruce—and a more uniform response to decay fungi across wood species. Overall, despite its darker appearance, the lignin-based formulation offered functional protection comparable to the commercial coating, confirming its potential as a viable bio-based alternative for above-ground wood applications.

Norway spruce (Picea abies L. Karst.) is a commercially valuable species, but has low permeability and susceptibility to decay, which requires an effective preservative treatment. In this study, the effect of microwave (MW) pretreatment on preservative retention and durability of wood during 30 months of outdoor exposure was investigated. MW-treated specimens showed a significant increase in preservative retention of borax-boric acid (BBA), with MW 36 treated specimens showing a retention of 40.79 kg/m3 compared to 7.90 kg/m3 for untreated controls. Durability assessment revealed that the MW treated specimens remained decay-free at higher energy levels (MW 28, MW 32, MW 36), whereas the untreated controls reached decay ratings of 3 in open conditions and 2 in shaded environments. Structural and chemical changes, including increased permeability, lignin content and crystallinity might have contributed to the increased resistance of MW-treated wood to fungal decay. The study also highlights the influence of climatic factors on the progression of decay, with MW pretreatment resulting in significant improvement in resistance to moisture-induced degradation. While lower MW energy levels (MW 20, MW 24) showed slight fungal growth, higher energy levels provided sustained protection, establishing the effectiveness of MW pretreatment as a promising technique to augment preservative retention and improve the in-service durability of wood. Future research should therefore investigate the mechanical effects, economic feasibility, and long-term performance of different commercial species in the field under different climatic conditions. The present study demonstrates that microwave pretreatment synergistically enhances the efficacy of BBA, which is a waterborne leachable but relatively safe wood preservative, potentially diminishing exclusive reliance on traditional toxic chemical preservatives to improve wood durability.

The surfaces of beech wood samples were treated with polyethylenimine (PEI) solutions at three different concentrations—0.5%, 1% and 2%—and two molecular weights—low molecular weight (LMW) and high molecular weight (HMW). The effects of PEI surface treatment of wood were characterized by FT-IR spectroscopy, the penetration depth of PEI (EPI fluorescence spectroscopy), the bonding position of PEI (by SEM), the wetting and surface energy, and the water uptake. After PEI treatment, the samples were coated with a water-based transparent acrylic coating (WTAC). The dry film thickness, the penetration depth of the coating, the adhesion strength and the surface roughness of the coated wood surface were evaluated. EPI fluorescence and SEM micrographs showed that PEI HMW chains were deposited on the surface, in contrast to PEI LMW, which penetrates deeper into layers of the wood cells. Treatment with a 1% PEI HMW solution resulted in a 72% reduction in water uptake of the wood (compared to untreated samples after 5 min of applying water droplets to the surface) and a 23.2% reduction in surface energy (compared to untreated samples) while maintaining the adhesion strength of the applied WTAC. The lower water uptake of the treated wood samples reduced the roughness of the coated surface, which is particularly important when the wood surface is finished with water-based coatings.

This study investigates the in situ synthesis and formation of zinc oxide (ZnO), silicon dioxide (SiO 2 ), and titanium dioxide (TiO 2 ) particles within the wood structure to modify the wood surface, aiming to improve the hydrophobicity, UV resistance, and antifungal properties of Scots pine and Norway spruce wood. The formation of particles in the modified wood and untreated wood surfaces was characterised using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) to study the microstructure and chemical composition, X-ray diffraction (XRD) to determine the type of crystallisation, and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to analyse the bonding forces. Results indicated that TiO 2 and SiO 2 treatments significantly improved both wood species’ surface hydrophobicity and UV resistance properties compared to ZnO-treated wood. On the other hand, ZnO treatment enhanced antifungal properties, offering effective protection against fungal decay in both wood species, while TiO 2 and SiO 2 showed less pronounced effects. This study showcases the potential of ZnO, SiO 2 , and TiO 2 particle treatments to enhance the surface properties of natural wood, paving the way for the effective and environmentally friendly development of hybrid wood for various applications in the wood industry and beyond.

Na letošnjem 56. letnem srečanju Svetovnega združenja za zaščito lesa, International Research Group on Wood Protection, IRG/WP, v Jokohami na Japonskem, ki je potekalo od 22. do 26. 6. 2025, je bil prof. dr. Miha Humar z Oddelka za lesarstvo Biotehniške fakultete Univerze v Ljubljani izvoljen za predsednika s triletno mandatno dobo. V prispevku je predstavljeno združenje IRG/WP in njegova zgodovina, organiziranost ter mednarodni pomen. Opisano je sodelovanje slovenskih znanstvenic in znanstvenikov v tem združenju, ki ima dolgo in pomembno zgodovino. V nadaljevanju je orisano delo in znanstveni dosežki prof. dr. Miha Humarja ter pomen za Slovenijo, da je slovenski znanstvenik prevzel vodenje uglednega svetovnega združenja.

Wood is an organic material that is highly susceptible to moisture, which compromises its performance, accelerates decay, and promotes mould growth, thereby reducing its service life. This study presents a comparative assessment of cost-effective solutions for enhancing the hydrophobicity, mechanical properties, and blue-stain resistance of wood surfaces by evaluating the effects of silicon dioxide (SiO2), zinc oxide (ZnO), and titanium dioxide (TiO2) particle coatings on Scots pine wood. Low-concentration particles were applied via an impregnation coating method, resulting in the formation of a nanocomposite between the wood and the particles. The coated and uncoated samples were then exposed to blue-stain fungi. To further analyse the effects, the exposed samples were characterised using scanning electron microscopy (SEM) to analyse particle morphology and observe fungal colonisation, and energy-dispersive X-ray spectroscopy (EDS) to determine elemental distribution. Fourier-transform infrared spectroscopy (FTIR) was used to confirm interactions between the nanoparticles and wood components. Mechanical and physical tests were conducted to evaluate the durability and resistance of the coated wood against blue-stain fungi. The results showed a significant improvement in surface hydrophobicity following coating application, which remained stable even after exposure to fungi. Moreover, distinct differences in fungal resistance were observed among the nanoparticle types, with ZnO showing the highest effectiveness. A new approach was also introduced to assess the mechanical performance of the coatings. This study offers insight into nanoparticle coatings as a sustainable strategy for enhancing wood surfaces in construction and outdoor furniture applications.

Norway spruce (Picea abies) is often used in construction but is difficult to impregnate with wood preservatives due to pit aspiration, limiting its treatability. The low natural durability of spruce necessitates preservation treatments. Microwave treatment improves the permeability, increasing preservative retention and penetration. However, treatability assessment has often been conducted using visual methods, which can over - or underestimate success. This study used image processing to evaluate MW-treated spruce's treatability with two water-based preservatives. The effect of MW treatment at five energy levels was analysed for sapwood and heartwood. The results showed improved retention values and penetration percentages for the MW-treated sapwood and the heartwood. The retention values of both preservatives increased between 50% and 124% for different treatment combinations. Spruce heartwood MW-treated with 1260 MJ/m3 improved treatability by 24% when analysed with ImageJ. The anatomical analysis showed that the effect of MW on heartwood was more pronounced than on sapwood, leading to the destruction of rays and parenchyma cells that facilitated the absorption and penetration of the preservatives. The study demonstrates the potential of ImageJ for more accurate treatability assessment and suggests that MW treatment if optimised, could improve the natural durability of spruce wood.

We investigated the applicability of the instrumented microscratching and microindentation methods in the examination of fungal decay of wood. Samples of Norway spruce wood (Picea abies) were exposed to the brown rot fungus Gloeophyllum trabeum using the mini-block method. The decay progression was monitored at one-week intervals during the 8-week fungal exposure. The results were complemented by hyperspectral imaging. In contrast to the progression of fungal decay, measured by mass loss of wood samples and where decay could only be detected five weeks after exposure, signs of decay could be detected by microscratching and microindentation measurements after only two weeks of exposure.

This study investigates the effectiveness of microwave treatment (MW) on the antifungal properties of Norway spruce wood and the leaching of preservatives. Given the environmental and health concerns about conventional wood preservatives, this study evaluates microwave treatment as a sustainable pretreatment to limit the leaching of preservatives from wood. In the experiment, wood samples were treated with microwaves at five different energy levels before being impregnated with copper–ethanolamine- and boron-based preservatives. We assessed preservative retention by leaching tests and assessed the resistance of the wood to fungal attack. The results show that MW treatment improves the uptake and fixation of preservatives, reduces leachability, and significantly improves the durability of an otherwise perishable wood against fungal attack. This study emphasises the potential of microwave treatment for wood preservation. It offers an environmentally friendly approach to extending the life of wood products while maintaining their protective properties against decay.

The measurement of charmonium states produced in proton-neon ( pNe ) collisions by the LHCb experiment in its fixed-target configuration is presented. The production of J/ψ and ψ(2S) mesons is studied with a beam of 2.5 TeV protons colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy √(s_NN) =68.5 GeV . The data sample corresponds to an integrated luminosity of 21.7± 1.4 nb ^-1 . The J/ψ and ψ(2S) hadrons are reconstructed in μ ^+ μ ^- final states. The J/ψ production cross-section per target nucleon in the centre-of-mass rapidity range y^⋆∈ [-2.29, 0] is found to be 506 ± 8 ± 46 nb/nucleon . The ratio of J/ψ and D^0 cross-sections is evaluated to (1.06 ± 0.02 ± 0.09)% . The ψ(2S) to J/ψ relative production rate is found to be (1.67 ± 0.27± 0.10)% in good agreement with other measurements involving beam and target nuclei of similar sizes.

The decay B- -> Lambda(+)(c)(Lambda) over bar K--(c)- is studied in proton-proton collisions at a center-of-mass energy of root s = 13 TeV using data corresponding to an integrated luminosity of 5 fb(-1) collected by the LHCb experiment. In the Lambda K-+(c)- system, the Xi(c)(2930)(0) state observed at the BABAR and Belle experiments is resolved into two narrower states, Xi(c)(2923)(0) and Xi(c)(2939)(0), whose masses and widths are measured to be m(Xi(c)(2930)(0) = 2924.5 +/- 0.4 +/- 1.1 Mev, m Xi(c)(2930)(0)) = 2938.5 +/- 0.9 +/- 2.3 Mev, Gamma(Xi(c)(2930)(0)) = 4.8 +/- 0.9 +/- 1.5 MeV, Gamma(Xi(c)(2930)(0) - 11.0 +/- 1.9 +/- 7.5 MeV, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Lambda K-+(c)- sample. Evidence of a new Xi(c)(2930)(0) state is found with a local significance of 3.8 sigma, whose mass and width are measured to be 2881.8 +/- 3.1 +/- 8.5 MeV and 12.4 +/- 5.3 +/- 5.8 MeV, respectively. In addition, evidence of a new decay mode Xi(c)(2930)(0) -> Lambda K-+(c) is found with a significance of 3.7 sigma. The relative branching fraction of B- -> Lambda(+)(c)(Lambda) over bar K--(c)- with respect to the B- -> D+D-K- decay is measured to be 2.36 +/- 0.11 +/- 0.22 +/- 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.

Abstract The first measurement of $${{J}/\psi }$$ J / ψ and $${{D}} ^0$$ D 0 production in PbNe collisions by the LHCb experiment in its fixed-target configuration is reported. The production of $${{J}/\psi }$$ J / ψ and $${{D}} ^0$$ D 0 mesons is studied with a beam of lead ions with an energy of 2.5 $$\,\text {TeV}$$ TeV per nucleon colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy of $$\sqrt{s_{\scriptscriptstyle \text {NN}}} =68.5\,\text {GeV} $$ s NN = 68.5 GeV . The $${{J}/\psi }$$ J / ψ / $${{D}} ^0$$ D 0 production cross-section ratio is studied as a function of rapidity, transverse momentum and collision centrality. These data are compared with measurements from $$p\text {Ne}$$ p Ne collisions at the same energy and show no difference in the observed $${{J}/\psi }$$ J / ψ suppression trend when comparing $$p\text {Ne}$$ p Ne and PbNe peripheral collisions with PbNe central collisions.

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a Z boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 < pT < 100 GeV and in the pseudorapidity range 2.5 < ? < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb(-1). Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.

We report on a measurement of the Lambda(+)(c) to D-0 production ratio in peripheral PbPb collisions at root sNN = 5.02TeV with the LHCb detector in the forward rapidity region 2 < y < 4.5. The Lambda(+)(c) (D-0) hadrons are reconstructed via the decay channel Lambda(+)(c) -> pK(-)pi(+) (D-0 -> K- pi(+)) for 2 < pT < 8 GeV/ c and in the centrality range of about 65-90%. The results show no significant dependence on pT, y or the mean number of participating nucleons. They are also consistent with similar measurements obtained by the LHCb collaboration in pPb and Pbp collisions at root sNN = 5.02TeV. The data agree well with predictions from PYTHIA in pp collisions at root s = 5TeV but are in tension with predictions of the Statistical Hadronization model.

A search for the very rare D^{0}→μ^{+}μ^{-} decay is performed using data collected by the LHCb experiment in proton-proton collisions at sqrt[s]=7, 8, and 13 TeV, corresponding to an integrated luminosity of 9  fb^{-1}. The search is optimized for D^{0} mesons from D^{*+}→D^{0}π^{+} decays but is also sensitive to D^{0} mesons from other sources. No evidence for an excess of events over the expected background is observed. An upper limit on the branching fraction of this decay is set at B(D^{0}→μ^{+}μ^{-})<3.1×10^{-9} at a 90% C.L. This represents the world's most stringent limit, constraining models of physics beyond the standard model.

15th Meeting of the Alumni Club of the Departmentof Wood Science and Technology BF UL