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The objective of this study was to determine suitable tree species to monitor and reduce Sn concentrations in the environment of Düzce province in Türkiye. A further goal was to test the hypothesis that, possibly due to air transport, the uptake of Sn in tree rings would show a significant and consistent dependency on compass direction. The timber samples were from the trunks of Tilia tomentosa (linden), Robinia pseudoacacia (black locust), Cedrus atlantica (cedar), Pseudotsuga menziesii (Douglas fir), and Fraxinus excelsior (European ash), which are commonly used in landscaping in Düzce province. Levels of Sn concentrations in annual rings were determined. Cedrus atlantica and F. excelsior were found to be suitable biomonitors that can be used to monitor changes in annual amounts of Sn contamination. Among the studied tree species, R. pseudoacacia had the highest average values and C. atlantica had the second-highest levels of Sn uptake. However, no consistent dependency on compass direction was found. It follows that rather than depending on the direction of prevailing winds, the uptake of metals to the xylem of trees must be due to direction-independent processes, such as transport via roots and xylem or absorption into leaves and subsequent transport via the phloem. [ABSTRACT FROM AUTHOR]

The concentrations of Sr, Tl, and V in soils and plant organs were evaluated at a copper mining site. These are heavy metals that are extremely dangerous and harmful to human and environmental health and, therefore, are on the ATSDR substance priority list. Within the scope of the study, soil samples were taken from different soil depths in the spoil area, the rehabilitation area where planting was performed and adult trees that were at least 20 years old, and the forest area. Soil samples were taken from the rehabilitation and forest areas where Pinus nigra Arnold., Pinus sylvestris L., and Robinia pseudoacacia L. species grow, and leaf, bark, wood, and root samples were taken from trees in the same areas. The study evaluated variations in heavy metal concentrations in soils based on species and soil depth and in plants based on plant species and organs. The study found that the heavy metal concentrations in soils and plant organs generally varied depending on plant species, while these variations were insignificant depending on soil depth. The highest concentrations by species were generally obtained for Sr in Robinia pseudoacacia and for Tl and V in Pinus nigra. [ABSTRACT FROM AUTHOR]

This study aimed to determine the most suitable woody species that can be used to reduce the pollution of Sr, Mo, and Sn, which are heavy metals that are harmful to the ecosystem and human and environmental health. Within the study's scope, samples were taken from the wood parts of 16 woody species growing under similar conditions in Düzce province, which is among the five cities with the most polluted air in Europe. The wood part is the largest organ of higher plants in terms of mass; it traps heavy metals within itself for many years and can remove heavy metals to a great extent. Therefore, plants with a high potential for heavy metal accumulation in the wood part are among the most suitable plants for phytoremediation studies. The study determined Sr, Mo, and Sn concentrations in the wood parts of 16 tree species via inductively coupled plasma optical emission spectroscopy and compared them using statistical methods. Results indicate that Robinia pseudoacacia and Cedrus atlantica species were suitable for reducing pollution by Mo and Sn, while Platanus orientalis and Populus alba species were suitable for reducing Sr pollution. [ABSTRACT FROM AUTHOR]

To improve the appearance of the black locust wood under heat treatment, ammonia (AM), acetic acid (AA), and ammonium acetate (AMA) were adsorbed into the black locust wood flour, with or without aluminum sulfate octadecahydrate (ASO). The color parameters (CIE L*a*b*) of the black locust wood flour treated with different conditions were measured. Diffuse reflectance ultraviolet-visible spectroscopy (DRUV-Vis) and the attenuated total reflection/Fourier transform infrared spectroscopy (ATR-FTIR) were conducted to reveal the changes of the chromophore systems. X-ray photoelectron spectroscopy (XPS) was used to demonstrate the extreme valence of the atomic content and the occurrence of a coordination reaction. The color of the wood flour became reddish after the treatment with AMA+ASO. There was an increase in carbonyl structure and carboxyl structure of the wood flour treated with AMA and ASO. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi can increase the biomass of host plants that are used as biofuel feedstock. However, little is known about the effects of AM fungi during aqueous ammonia pretreatment of biomass to remove lignin or on the enzymatic hydrolysis of cellulose. The analysis of mycorrhizal colonization (Rhizophagus irregularis or Glomus versiforme) on stems of black locust (Robinia pseudoacacia) plants in their first and second year of growth revealed that the presence of AM fungi and the growth time significantly influenced the lignin and cellulose content of untreated black locust but had no effect on the content of stems pretreated with aqueous ammonia. The presence of AM fungi and/or the growth time also affected the black locust stem structure and the chemical structure of lignin. Hydrolysis of mycorrhizal and non-mycorrhizal biomass produced similar glucose yields (except for the second-year R. irregularis biomass, which produced significantly less glucose than the other treatments). The results suggest that mycorrhizal black locust biomass is a suitable substrate for biofuel production. [ABSTRACT FROM AUTHOR]

The article presents research on the effect of the sharpness angle on the quality of machined surface of native wood species (pine, beech, and black locust) and an exotic species called iroko. Four sharpness angle values were analyzed at 25, 40, 45, and 55°. The experiment was conducted on a bottom-spindle milling machine, with a constant spindle rotational speed (6000 min-1) and four feeding speeds of 3.2, 8.3, 12.5, and 16.7 m/min. The influence of sharpness angle, feeding speed, and wood species on the quality of machined surface of wood was determined. The optimum ranges of the sharpness angle were established with respect to wood surface quality. The surface roughness of the samples decreased with decreasing in the sharpness angle in range of 55° to 40°. The optimal value of the angle was 40°, and the roughness increased with increasing feeding speed. It was found that an increase in wood density decreased surface roughness. [ABSTRACT FROM AUTHOR]

To investigate the effects of phenolic extractives on the discoloration of black locust wood (Robinia pseudoacacia) during heat treatment, phenolic compounds were extracted using an accelerated solvent extraction. The main components of the phenolic extractives were analyzed. The phenolic compounds were heat treated at 120 and 140 °C in nitrogen, oxygen, and saturated steam. The results showed that the a* values shifted toward red and the b* values shifted toward yellow after the heat treatment. The changes in the color parameters were more pronounced when the samples were treated at 140 °C in saturated steam compared with treatment at 120 °C in oxygen or nitrogen atmosphere. During heat treatment, hydroxyl groups in the phenolic components were oxidized to form carbonyl groups, or the adjacent hydroxyl groups formed quinoid structures. It was possible that the sample underwent condensation reactions to produce conjugated double-bond structures that led to the increase in color parameters. [ABSTRACT FROM AUTHOR]

In this paper a dependence of the main cutting force upon several machining parameters by wood of black locust (Robinia pseudoaccacia L.) during straight turning was graphically illustrated and analyzed. Evidence for several interactions was found based on multi-factor nonlinear equations evaluated from an experimental matrix.

This paper utilized 12 coating systems, based on an acrylate and a hydrophobic polymer, with the addition of light pigments, nano-sized polyvalent metal (AsS-chelate complex) for ultraviolet protection, and iodopropynyl butylcarbamate fungicide. This study deals with the impact of the number of coats on the color stability and the surface defects of painted black locust (Robinia pseudoacacia L.) and Norway spruce (Picea abies Karst L.) woods after up to three years of natural weathering, at a slope of 45°. The best coating system was created from three coats, which consisted of two pigmented acrylates (PerlColor) and one transparent hydrophobic water-repellent (AquaStop). The total color change, ΔE*, of the weathered surfaces was approximately two times lower when the application involved a pigmented coating system compared with a transparent one. The color stability of the surfaces and their resistance to defects was better when the coating system was applied to black locust wood compared with spruce wood. Smoother surfaces of wood before painting resulted in a higher resistance against cracking and other defects caused by natural weathering; however, the effect of the initial wood roughness on the color stability of painted woods during natural weathering was usually negligible. [ABSTRACT FROM AUTHOR]

Different solvent fractions (Fs) of water:methanol (1:1 v/v) of heartwood, bark, and leaf extracts of Robinia pseudoacacia were evaluated for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method; the antifungal activity against the mycelial growth of Trametes versicolor fungus was also determined. The most active fractions were analyzed for their chemical composition using gas chromatography- mass spectrometry (GC/MS). At higher concentrations (0.016 mg/mL), the values of antioxidant activity were 92.3%, 92.5%, 50.6%, 93.4%, and 96.6%, for heartwood F7 (ethyl acetate fraction), bark F7 (ethyl acetate fraction), leaves F9 (methanol fraction), BHT, and vitamin C, respectively. Among the fractions and concentrations of extracts from heartwood, F7 at 12.5 ppm led to the lowest growth of T. versicolor (22.00 mm); F7 of the bark extract showed good antifungal activity, with lower mycelia growth values reached 11.33, 11.33, and 13.00 mm at concentrations of 12.5, 25, and 50 ppm, respectively. For leaf extracts, F9 showed good antifungal activity at all concentrations, where the values of mycelial growth were 26.00, 25.33, and 28.33 mm at concentrations of 12.5, 25, and 50 ppm, respectively. These results indicated that the fractions of R. pseudoacacia can be a valuable and economic resource for use in antioxidant activity or as an antifungal activity against the growth of T. versicolor. [ABSTRACT FROM AUTHOR]

The colour change of wood has been the topic of numerous research activities worldwide. This study investigates the colour change of Robinia (Robinia pseudoacacia L.) and two hybrid poplars, namely Pannónia poplar (Populus x euramericana cv. Pannónia) and I-214 poplar (Populus x euramericana cv. I-214). The sapwood and heartwood were investigated separately for each of the poplars. The heartwood of Robinia was also investigated. The timbers were dried in a climate chamber at four different temperatures (20 °C, 40 °C, 60 °C, and 80 °C), as the relative humidity was reduced in 5 steps (95%, 80%, 65%, 40%, and 20%) at each temperature. The colour co-ordinates L*, a*, and b* were measured according to the CIELab system. Differences in terms of colour change between wood species and sapwood versus heartwood are discussed in the paper. The effect of wood moisture content and heat on the colour co-ordinates is provided. The colour of Robinia is more sensitive to heat than poplar. [ABSTRACT FROM AUTHOR]

Three softwood species, spruce (Picea abies Karst.), fir (Abies alba Mill.), and larch (Larix decidua Mill.), and five hardwood species, oak (Quercus petraea Liebl.), ash (Fraxinus excelsior L.), beech (Fagus sylvatica L.), cherry (Prunus avium L.), and black locust (Robinia pseudoacacia L.) were treated at high temperatures under vacuum conditions with Termovuoto® technology. All of the wood species were treated at different temperatures (from 160 to 220°C), different times (from 45 minutes to 5 hours), and under different pressure conditions (160, 210, and 330 mbar). The treated material was characterized in terms of mass loss, color changes, and equilibrium moisture content. Results showed dissimilar behavior of various wood species and their different sensitivities to treatment schedules. Consequently, the series of tests performed allowed a detailed characterization of the Termovuoto® process and its effect on product quality. [ABSTRACT FROM AUTHOR]

To investigate chemical and color changes of the polymeric constituents of black locust (Robinia pseudoacacia) wood during heat treatment, extractive-free wood flour was conditioned to 30% initial moisture content (MC) and heated for 24 h at 120 °C in either an oxygen or nitrogen atmosphere. The color change was measured using the CIELAB color system. Chemical changes of the wood components were determined by means of solid state cross-polarization/magic angle spinning 13C-nuclear magnetic resonance (CPMAS-13C-NMR), Fourier transform infrared (FTIR), diffuse reflectance UV-Vis (DRUV) spectroscopy, and elemental (CHN) analysis. The results showed that lightness (L) decreased, while chromaticity indexes (a* and b*) and chroma (C) increased after heat treatment. There was greater color difference (ΔE*) in the samples heated in the presence of oxygen compared to nitrogen. CHN analysis showed an increase in hydrogen and oxygen and a decrease in carbon content. NMR spectra confirmed the cleavage of the β-O-4 structure in the lignin, resulting in a decrease in etherified lignin units and an increase in phenolic structures. DRUV and FTIR spectra confirmed the formation of extensive conjugated structures, such as unsaturated ketones and quinones due to the cleavage of the lignin units. Formation of quinones can be attributed to heat treatment in the presence of oxygen. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of oxygen and moisture content (MC) on the chemical and color changes of black locust (Robinia pseudoacacia) wood during heat treatment. The wood flour was conditioned to different initial MCs and heated for 24 h at a constant temperature of 120°C in either oxygen or nitrogen atmosphere. The pH values and chromaticity indexes were examined. Diffuse reflectance UV-Vis (DRUV) and Fourier transform infrared (FTIR) spectra were used to characterize the changes of chromophores upon heating. The study demonstrated that the pH values decreased after heat treatment, and it was lower when the heat treated was in oxygen than in nitrogen. The L* decreased significantly, while a* and b* increased. The total color difference ΔE* increased with increasing initial MC until a plateau was reached after 30% MC. The color change was greater in oxygen than in nitrogen. The hydroxyl groups decreased after heat treatment. The releases of acid and formation of quinoid compounds and carboxylic groups during heat treatment were confirmed. Discoloration of wood is due mainly to the condensation and oxidation reactions, which are accelerated by oxygen. Higher MCs are required to obtain the greatest color change of wood in inert atmosphere. [ABSTRACT FROM AUTHOR]