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Aluminium titanate - tialite belongs to the compounds with pseudobrookite structure. The polycrystals made of tialite show valuable useful thermal properties: low thermal expansion, very low thermal conductivity and high resistance to thermal shock. These properties result from the cracks present in the microstructure, resulting from significant differences in the lattice coefficients of aluminium titanate. The basic disadvantage of tialite consist in a thermal decomposition occurring at the temperatures of about 750–1280 °C. This decomposition can be limited by structural and microstructural stabilization. The addition of cations, e.g. magnesium or iron, leads to the formation of stable solid solutions, while the addition of SiO2 or ZrO2 leads to the formation of secondary phases - diffusion barriers occurring at intergranular boundaries. Most often these additives are introduced simultaneously and at the reaction sintering stage. Stable solid solutions are usually produced by a classical solid phase reaction between the initial oxides: Al2O3, TiO2 and MgO. In this work, an innovative synthesis was applied to produce solid solutions, involving a heterogeneous isostructural nucleation with magnesium titanate. The polycrystals obtained in this way, at a much lower temperature, with a high content of solid solutions (95–96 %), high density, homogeneous microstructure with necessary microcracks were obtained. As a result, the obtained polycrystals exhibit the typical pseudobrookite structure behaviour as a function of temperature.

There is strong evidence that neuronal bases for language processing are remarkably similar for sign and spoken languages. However, as meanings and linguistic structures of sign languages are coded in movement and space and decoded through vision, differences are also present, predominantly in occipitotemporal and parietal areas, such as superior parietal lobule (SPL). Whether the involvement of SPL reflects domain-general visuospatial attention or processes specific to sign language comprehension remains an open question. Here we conducted two experiments to investigate the role of SPL and the laterality of its engagement in sign language lexical processing. First, using unique longitudinal and between-group designs we mapped brain responses to sign language in hearing late learners and deaf signers. Second, using transcranial magnetic stimulation (TMS) in both groups we tested the behavioural relevance of SPL’s engagement and its lateralisation during sign language comprehension. SPL activation in hearing participants was observed in the right hemisphere before and bilaterally after the sign language course. Additionally, after the course hearing learners exhibited greater activation in the occipital cortex and left SPL than deaf signers. TMS applied to the right SPL decreased accuracy in both hearing learners and deaf signers. Stimulation of the left SPL decreased accuracy only in hearing learners. Our results suggest that right SPL might be involved in visuospatial attention while left SPL might support phonological decoding of signs in non-proficient signers.

Inconel 625-NbC Metal Matrix Composite (MMC) is an emergent material of Inconel 625-carbide composites. It is characterized by dense microstructure, improved hardness, and preserved passive Cr-rich layer formation during oxidation. In this study, its thermal properties were investigated. Inconel 625-NbC composites and Inconel 625 reference alloy were consolidated by Spark Plasma Sintering (SPS). Their microstructure, phase composition, Coefficient of Thermal Expansion (CTE), thermal diffusivity (alpha), thermal conductivity (lambda), and specific heat (c(p)) were studied. The addition of NbC into Inconel 625 matrix did not significantly affect the CTE or lambda of the final composite. Thermal conductivity of Inconel 625-NbC was initially lower than 625 superalloy but was increasing faster in function of temperature. c(p )functions of SPS-ed 625 alloy and composites had different slopes in comparison to literature. The influence of hot rolling, part of Inconel 625-NbC obtaining SPS technology, was also studied. It affected composites c(p).

The study aimed to answer the question of previously obtained Inconel 625-NbC metal matrix composites (MMC) applicability in high-temperature and/or oxidative environments, that were proven to possess improved mechanical properties. To achieve that goal, a similar manufacturing process was performed, utilizing spark plasma sintering (SPS) at 1100 degrees C under 45 MPa, and in a medium vacuum (under 10-3 MPa). The total time for each sample equaled 60 min. Four sets of samples were obtained with ceramic reinforcement additions equaling 0, 5, 10, and 20 wt%. Hot rolling at 1100 degrees C with a 10% reduction step was applied to sintered materials in order to fully replicate previous technology. Oxidation tests were performed in furnaces with free flow of air for three total time periods: 24, 49, and 100 h at 800 degrees C. It was revealed that all samples kept their ability to form passive layers by matrix, but those layers were locally breached due to grain growth and thermal stresses of the oxidized reinforcement phase. Two different passive layer formations were observed and discussed: (Cr/Ni)-rich covering composite surface and (Cr/Nb)-rich forming around ceramic reinforcement. Total mass gain during oxidation was kept under 1 mg/cm2 for each sample series, with samples containing 5 wt% of NbC performing similarly to reference material. Hardness loss (up to 15%) was observed in near-surface zones of obtained MMC due to composite oxidation.

In the work the SHS synthesis of MAX phases from Ti-Si-C system were carried and initiated with use of 30 W laser beam with 40 µm spot. That kind of initiation allows locally and rapidly start the SHS synthesis and avoid the contamination coming from heating wire present during conventional method. The reaction was monitored by high-accuracy radiation pyrometer and high quality optical camera. The recorded data, together with reaction bed thermal conductivity measurements allowed to correlate to obtained powders composition and reaction speed. The reaction bed morphology was investigated by scanning electron microscopy with element distribution (EDS). The second part of the paper concerns laser reactive deposition of SHS in-situ synthetized MAX phases layer on silicon carbide substrate. The paths of deposited layer were formed under argon overpressure of 2 bar using 120 W of laser power.

Silicon carbide/graphene platelet (SiC/GPLs) composites were prepared using different weight percent of GPLs filler by hot pressing (HP) technology at 2100 °C in argon. The influence of the GPLs addition on bending strength, fracture toughness and related fracture characteristics was investigated. Both the bending strength and fracture toughness increased with increasing GPLs additives. The main fracture origins – strength degrading defects were pores at the low content of platelets and combination of pores and GPLs or clusters of GPLs particles in systems with a higher content of platelets. The fracture toughness increased due to the activated toughening mechanisms mainly in the form of crack bridging and crack branching, while the crack deflection was limited. The highest fracture toughness of 4.4 MPa m1/2 was achieved at 6 wt.% of GPLs addition, which was ∼30% higher than the KIC value of the reference material.

Boron carbide/graphene platelet (B 4 C/GPLs) composites have been prepared with a different weight percent of GPLs as sintering additive and reinforcing phase, hot pressed at 2100 °C in argon. The influence of the GPLs addition on fracture toughness (K IC ) and electrical conductivity was investigated. Single Edge V-Notched Beam (SEVNB) method was used for fracture toughness measurements and the four-point Van der Pauw method for electrical conductivity measurements. With increasing amount of GPLs additives, the fracture toughness increased due to the activated toughening mechanisms in the form of crack deflection, crack bridging, crack branching and graphene sheet pull-out. The highest fracture toughness of 4.48 MPa.m 1/2 was achieved at 10 wt.% of GPLs addition, which was ∼50% higher than the K IC value of the reference material. The electrical conductivity increased with GPLs addition and reached the maximum value at 8 wt.% of GPLs, 1.526 × 10 3 S/m in the perpendicular and 8.72 × 10 2 S/m in the parallel direction to the hot press direction, respectively.

Inconel 625 - WC metal matrix composite is a very promising material for high temperature applications. In this study, microstructure investigation and phase composition of a mixture between Inconel 625 and fine tungsten carbide (φ≈0.64 µm) was performed by means of XRD, SEM with EDS and TEM with EDS. Two powder mixtures were prepared: 20 wt% of WC and 30 wt% of WC and deposited on Inconel 625 substrate by laser cladding obtaining a crack and pore free material. The high temperature of the process resulted in partial dissolution of WC in Inconel 625 matrix. In sample containing 30 wt% of WC appearance of topologically close-packed (TCP) phases was observed at grain boundaries. WC, W2C, NbC, W 6 C 2.54 and (W,Cr,Ni) 23 C 6 were detected by XRD. Angular residual carbides and spherical oxide precipitates were visible in both types of samples. Processes occurring during laser action were explained.

The friction and wear behaviour of hot pressed boron carbide/graphene platelets (GPLs) composites have been investigated using the ball-on-flat technique with SiC ball under dry sliding conditions at room temperature. The hardness and fracture toughness of the investigated materials varied from 18.21 GPa to 30.35 GPa and from 3.81 MPa·m1/2 to 4.60 MPa·m1/2, respectively. The coefficient of friction for composites were similar, however the wear rate significantly decreased ~ 77% in the case of B4C + 6 wt.% GPLs when compared to reference material at a load of 5 N, and ~ 60% at a load of 50 N. Wear resistance increased with increasing GPLs content in regards to the present graphene platelets, which during the wear test pulled-out from the matrix, exfoliated and created a wear protecting graphene-silicon based tribofilm.

The phytoextraction of arsenic (As) is dependent on numerous factors. One such factor is the specific interaction between As and other elements but there are also possible interactions of this metalloid form, present in both substrate and in plants. Thus an estimation was made of As(III), As(V) and cacodylic acid (DMA) phytoextraction in two-years old U. laevis seedlings, growing under diverse ratios of the above mentioned forms in solution. The pot experiment did not reveal any significant diversity in plant biomass growing in different systems, with the exception of DMA present in higher concentrations. However, diversity in phytoextraction of particular As forms and differences in their translocation were observed. All three forms were accumulated mainly in roots. Additionally, As(III) and As(V) were found in both roots and leaves, whereas DMA was only present in roots. The exposure of seedlings to higher concentrations of DMA was directly related to their rapid withering. The higher availability of As(III) or As(V) was generally associated with higher phytoextraction of these forms. Moreover, an increase in the concentration of As(V) in solution brought about the most effective phytoextraction of As(III). DMA was accumulated when As(III) was present in solution, while an adverse effect was observed for As(V).

The main problem of utilization of ceramic nanopowders consists in their tendency to form hard agglomerates. The inter-agglomerate space forms pores surrounded by numerous elementary particles (crystallites). Such pores cannot be easily removed from the system during pressureless sintering. So, the obvious strategy for a technologist is to eliminate such pores at the level of shaping operations. Dry pressing is a frequently applied shaping technique of ceramic materials. That is why mechanical strength of agglomerates should be as low as possible. It enables the elimination of inter-agglomerate pores to occur under moderate pressures, applied during the shaping process. This problem will be illustrated using the really nanometric (below 10 nm) zirconia-yttria solid solution powder. The methods of effecting agglomerate strength will be shown. One of the elaborated powder preparation rout results in extremely soft agglomerates.

Diamond-CaMg(CO3)2 and diamond-CaCO3 compacts were produced. Maximum values of high thermal conductivity of 540 W/m K, electrical resistivity of 2∙1011 ohm cm, dielectric constant of 47, and dielectric loss tangent of 5.8∙10-3 at 106 Hz were achieved. The composites based on diamonds were sintered at a high pressure of 8.0 GPa and temperature of 2100 °C and were characterised by high ratios of direct bonding between the diamond grains. Diamond grain size varied from 12 to 45 µm. The CaCO3 content of the diamond-CaCO3 composites and the CaMg(CO3)2 content of the diamond-CaMg(CO3)2 composites were 8.5 vol% and 8.8 vol%, respectively. The materials developed are recommended for use as heat sinks in a wide range of electronic devices.

Dense boron carbide–graphene composites were prepared by hot-pressing method. Phase analysis revealed presence of small amount of tungsten borides contamination in all sinters. Microstructure of composites showed orientation of graphene platelets. The anisotropy of wave velocity in ultrasonic measurements reached 25%. The values of thermal diffusivity and thermal conductivity were determined in different directions using laser flash analysis methods (LFA 427). For the composite containing 4 wt% of graphene platelets the anisotropy of thermal properties exceed 70%. Boron carbide–graphene composites were also examined in the field of thermal stability in air using DTA-TG apparatus. Oxidation of boron carbide started above 720 °C. Boron oxide layer formed on the surface was observed under scanning electron microscope.

Structure of hexagonal boron nitride (h-BN) consist of hexagonal layers with strong covalent bonds and weak van der Waals bonds between them. Such specific structure and usually plate-like grains cause anisotropic properties of h-BN based materials. The aim of the present work was preparation of composites in the aluminium oxynitride–hexagonal boron nitride system with anisotropic properties. SHS technique was used to obtain complex powders with both phases synthesized in situ . Mixtures of aluminium, aluminium oxide and different amount of boron were combusted in nitrogen and the powders were hot-pressed. The h-BN grains in the composites show plate-like shapes and crystallographic orientation. The specific microstructure and texture result in anisotropy of thermal properties; thermal conductivity was few times higher in the direction perpendicular to hot-pressing force and parallel to the longer diameter of h-BN grains. The texture effect is stronger than the effect of the h-BN content.

The study concerns a new material with an aluminum nitride matrix and a graphene additive. The material was obtained by the hot-pressing method. The material prepared in this way shows the anisotropy of the microstructure. This study focuses mainly on the microstructure of the material. The research contains the microstructure observation of sintered bodies, examination of the phase composition and identification of phases in the composites using the EDS method. Additional SEM observations of generated material fractures were made. Microstructural images were taken using computer-aided analysis, which gave the following parameters: coefficient of particle orientation, phases content, particle size. Such investigation was fulfilled by ultrasonic measurement of an anisotropy of longitudinal wave velocity, which gave an answer to the graphene orientation in the composites.

European ash (Fraxinus excelsior L.) dieback affects both overstory trees and natural regeneration. The decline of ash caused by severe crown defoliation and branch mortality has a high impact on ash natural regeneration. The site factors affecting the disease symptoms vary significantly and are not fully understood. Hence, we aimed to assess the joined effects of soil fertility and moisture (expressed by soil pH, CaCO3 content, and summer groundwater table level), herbivory, and health conditions connected with Hymenoscyphus fraxineus (T. Kowalski) Baral, Queloz, and Hosoya infestation on natural regeneration of F. excelsior. We examined 32 ash stands in Western Poland across soil fertility gradient. We established randomly selected circular plots (400 m2) in forests with ≥60% of ash in overstory species composition. We assessed natural regeneration density, the proportion of browsed trees, and trees damaged by ash dieback using generalized mixed-effects models. We found a higher proportion of damaged trees in neutral and base soils than in acid soils. Moreover, we found a low proportion of damaged trees in sites with low groundwater table levels. High CaCO3 content decreased the proportion of browsed trees, similarly as high shrub cover. The density of F. excelsior natural regeneration depended on groundwater table level, canopy cover, and proportion of damaged trees. We also found a positive relationship between density and deer browsing. The factor responsible for the higher infestation of saplings (low groundwater table level) also influenced natural regeneration density. This way, our study revealed how soil properties influence ash natural regeneration directly and indirectly. We showed that ash dieback will have a more severe impact on ash regeneration in ash typical sites. This is essential for predicting forest recovery and the ability to resilience after disturbances caused by H. fraxineus. Capsule Joined effects of ash dieback, soil pH, and CaCO3 content, together with soil moisture, as well as deer browsing, affect ash regeneration.

Due to the low hardness and poor tribological behavior of titanium alloys, surface coating is a very critical technique in order to increase their commercial exploitation. In this case, Al2O3-based coatings are very promising for these alloys to improve their surface properties. To increase the absorption of the laser light in the visible range, MnO2 is proposed as a dopant for Al2O3, in order to achieve dense coatings on Ti6Al4V substrates via cladding with a JK fiber laser. To ensure a homogeneous doping, MnO2 and Al2O3 were dispersed by means of ammonium citrate, and to fully cover the substrate, spray dried MnO2 doped Al2O3 granules were prepared and applied to the substrate. The effects of the solid loading on the properties of these granules were investigated. It is found that with 1.0 wt% MnO2 addition, a dense and uniform Al2O3 layer, accompanied with an interlayer, was successfully fabricated through laser cladding with low laser power of 20 W. Owing to the better adhesion on the substrate, Al2O3 coating on sandblasted substrates feature a higher hardness of 1204.1 ± 66.9 HV0.05 and an elastic modulus of 212.0 ± 11.8 GPa, which is an increase of 165.5% and 53.3%, respectively, compared to the as-received substrate.

Silicon nitride exhibits good thermal shock resistance and, therefore, it can be shaped by laser processing. Generally, laser treatment mostly depends on wavelength absorption, surface quality and thermal conductivity. Subtractive laser processing is an efficient method of modification up to 1500 µm depth and usually runs in pulse working (PW) mode. In case of continuous work (CW) mode, intensive processing conditions can result in material destruction which is presented for reference in this paper. The previous research indicates that the hot pressing of the silicon nitride material with GPL particles allowed for obtaining a specific orientation of the 2D graphene-like particles in the material. This led to the anisotropy of its thermal properties. As a result, the positive influence of the oriented heat flow on material laser ablation was investigated. The investigation of the Si3N4/GPLs confirmed the good quality of the laser cut which can proceed throughout the sample. The reported penetration depth reached over 3 mm. The laser treated areas were dimensionally measured and taken under optical and SEM/EDS observation.

We produced hexagonal ReB2-type IrB2 diboride and orthorhombic IrB monoboride phases, that were previously unknown and saw them produced by mechanochemical syntheses. High energy ball milling of elemental Ir and B powder for 30 h, followed by annealing of the powder at 1050 °C for 48 h, resulted in the formation of the desired phases. Both traditional laboratory and high resolution synchrotron X-ray diffraction (XRD) analyses were used for phase identification of the synthesized powder. Additionally, scanning electron microscopy and transmission electron microscopy were employed, along with XRD, to further characterize the microstructure of the phases produced.

Boron carbide (B 4 C) based composites, containing 4–10 wt% of graphene platelets (GPLs) as sintering additive (approximately 4 wt%) and reinforcing phase were prepared by hot-pressing (HP) at 2100 °C for 1 h. The effect of GPLs content on microstructure and mechanical properties has been investigated. All investigated mechanical properties were the highest in the case of B 4 C+4.5 wt% composite with bending strength of 398 MPa and fracture toughness of 5.89 MPa m 1/2 . Higher GPLs content resulted in lower mechanical properties except fracture toughness. Processing flaws in the form of GPLs agglomerates and structural inhomogeneities were identified as fracture origins. The main toughening mechanisms, responsible for the increased fracture toughness are crack deflection, crack branching and crack bridging.

The work presents a method of consolidation of graphene flakes (platelets) into a bulk material showing high anisotropy of thermal, electrical and mechanical properties. Such materials can be used as directional high-temperature thermal insulators similar to graphite foils, but due to much finer microstructure they may exhibit different, possibly enhanced properties. The graphene flakes were consolidated by a filter pressing of propanol suspension followed by a hot-pressing of produced green bodies at 2200 °C under 25 MPa in a protective atmosphere. The hot-pressing step was necessary to force orientation of the flakes and to densify the material. Microstructural observations, mechanical strength and elastic properties assessment, as well as thermal and electrical properties analysis were performed. Scanning electron microscopy revealed that microstructure of the material consisted of highly-oriented layers of the graphene flakes. It resulted in a distinct anisotropy of thermal conductivity (360 vs. 3 W/mK), coefficient of thermal expansion (25·10 −6 vs. −1·10 −6 1/K) and electrical resistivity (60·10 −6 vs. 850·10 −6 Ω m) of the material in the in-plane and through plane direction, respectively. The material showed brittle behavior, but it could be machined.

The study concerns silicon nitride based composites with an up to 10 wt% graphene nonoflakes (GNP) addition. An XRD and Raman analysis of hot-pressed prepared composites were conducted. The microstructural SEM observations supported by element EDS analysis were also made. Elastic and mechanical properties (Knoop hardness, bending strength, fracture toughness) were measured. The manufactured sinters were put to friction coefficient and wear tests. Wear scars on discs after the abrasion tests were observed by optical and SEM microscopy. Performance examinations of hot-pressed cutting tools were performed.

In the present study, boron carbide matrix composites were manufactured by hot-pressing method. In order to reduce the boron carbide sintering temperature and to improve the mechanical properties, such as bending strength, critical stress intensity factor and hardness, chromium carbide, because of its low melting point and high thermal expansion coefficient, was added in various volume quantities. In order to prepare the material for cutting tool or ceramics sealing applications hexagonal boron nitride in quantities ranging from 2 and 8 vol.% was added to reduce the friction coefficient. The sinters were subjected to the abrasive test and to elastic properties examinations. Computer simulations of thermal stresses were prepared. The measured mechanical properties were supported by phase analysis and microstructural observations. Because the carrying out of heat is very important for mechanical properties of materials the influence of additives on thermal conductivity was also presented.

This study presents the results of investigations concerning hot-pressing of submicron WC powders without sintering additives and with the addition of carbon or tungsten or both elements simultaneously. Dense polycrystals of diverse microstructures and phase compositions were obtained. Attempts were made to correlate a microstructure and phase composition of sinters with their thermal and mechanical properties. It was found that the presence of graphite nanolayers on grain boundaries in WC sinters with the addition of carbon favourably influences their thermal conductivity. All produced polycrystals are characterised by a high fracture toughness. The smallest scatter of KIc results is observed for compositions activated by a carbon addition. The presence of the graphite nanolayers as well as grain size in WC sinters with carbon additions reduce the polycrystal hardness. All WC polycrystals, regardless of introduced additives, are characterised by high bending strength and by high values of the Young and Kirchoff moduli. The tested polycrystals are not suitable for machining carbon steel of C45 grade.

A study on the preparation technique of composites in the NbC 0.95 – Cr y C z system is presented. It was found that, in comparison to samples of pure niobium carbide, chromium carbide additives lead to a decrease of the temperature at which shrinkage of the powder compacts starts. At temperatures lower than the temperature of the beginning of shrinkage, solid solutions of Cr and Nb carbides form. Microstructural observations indicate that a liquid phase appears at temperatures higher than the melting point of chromium carbide. It penetrates the niobium carbide matrix grain boundaries. This liquid phase improves densification of the systems and accelerates grain growth. In order to obtain fine-grained materials very high heating rate is necessary. Fully densified composites were received when the rate of temperature increase was equal to 30 °C/min.

Recently presented studies have revealed that micro-AlN–poly(propylene glycol) dispersions are of relatively low viscosity, shear-thinned, highly flowable and sufficiently time-stable. Such promising results have suggested that the fluids can be potentially applied as heat-transferring media. The AlN–PPG systems significantly differ from widely studied nanofluids, since they are highly loaded with micrometric solid phase. The presented paper focuses on three crucial features of AlN–PPG fluids – their stability, thermal conductivity and viscoelastic properties. Advanced analysis of AlN–PPG time stability was conducted in order to assess its applicable potential in thermal management technology. Thermal conductivity of AlN–PPG 425/2000 dispersions was measured and discussed. Thermal properties of the fluids were mostly dependent on their composition, i.e. solid phase loading and PPG molecular weight. Temperature did not substantially influence thermal conductivity of AlN–PPG fluids. Additionally, rheological response of AlN–PPG systems on oscillatory conditions was analysed. Linear viscoelastic range was determined and viscoelastic properties of the dispersions were recognised. The measurements provided useful rheological data about the structure of the dispersions and their temperature evolution.

The aim of this work was to determine selected Salix clones’ capacities for biomass production and accumulation of heavy metal ions. Determination of the relationship between sorption of metals and biomass productivity was a further purpose of this study. Eight Salix viminalis cultivars and one Salix alba cultivar were analyzed. The taxa characterized by greatest biomass production were S. alba var. Chermesina and S. viminalis ‘1056’ (respectively 6.8 and 4.3 kg of fresh mass per shrub per year). The results have revealed significant differences among clones. The clones most effective in accumulating all five metals were S. viminalis ‘1154’ and ‘1054’. The studied Salix population was significantly diverse as regards accumulation efficiency. The differences between the highest and lowest heavy metal content in extreme clones were for: Cd 84%, Cu 90%, Hg 167%, Pb 190% and Zn 36%. At the same time, significant differences were observed in Salix structure. The greatest cellulose content was observed in S. viminalis ‘Sprint’ (49.69%) and the lowest in S. viminalis ‘1059’ (42.09%).

The structure and properties of Ti3SiC2–TiB2 ceramic composites were investigated. A computer-aided image analysis, tests of mechanical properties as well as observation of the crack propagation mechanism were carried out for the Ti3SiC2–TiB2 composite at a TiB2 dispersed phase content varying from 5% to 50% by volume. The resulting data obtained made it possible to determine a relation between the TiB2 content and the mechanical properties of the composite; moreover, they revealed the way in which the presence of TiB2 particles in the composite matrix affected the course of cracks in the composite.

The aim of this study was to assess the accumulation of seven heavy metals (lead, cadmium, copper, zinc, chrome, nickel and cobalt). The investigations were conducted on twelve genotypes of willows which grow in the Potasze Forest Division Salicarium. The analysis facilitated quantification of concentrations of selected metals in plants and their comparison in relation to sorption ability of each willow genotype. Simultaneously the studies allowed us to demonstrate essential differentiation of metal size sorption within the species Salix purpurea and in relation to the other genotypes. The results confirm the complexity of factors influencing the efficiency of heavy metal accumulation by willow; they indicate increasing ion absorption in the case of some metals, while the accumulation of other heavy metal ions was limited.

This article focuses on the Polish structure NUM + na ‘out of’ + NUM (e.g. trzy na sto ‘three out of one hundred’). We explore the idea that, in most cases, the construction in question consists of a Determiner Phrase (DP) and an adjunct Prepositional Phrase (PP) – i.e. that it does not occupy a single numerical slot. We further postulate that this complex expression includes two occurrences of the quantified noun, one of them being subject to PF-ellipsis (deletion under identity). However, if the PP-internal (lower) numeral is a Q-type numeral (such as piec ‘five’), the construction may be reanalysed as ‘mono-phrasal’. In such cases, the whole expression forms only one DP and the lower Q-numeral becomes the head of the numerical complex. The analysis we put forward in the present paper is based on the assumption that Polish is a DP-type language. We also take Q-numerals to be functional heads which occupy Q° and take NPs as their complements.