Carbon and nitrogen isotope analyses coupled with palynological data of PM10 in Wrocław city (SW Poland)--assessment of anthropogenic impact

We have applied both palynological and carbon and nitrogen isotopic analyses of PM10 (particulate matter with a diameter of 10?μm or less) to trace its origin and to assess the anthropogenic impact for the area under study. The PM10 samples were collected in Wroc?aw (SW Poland) by the Regional Inspectorate for Environment Protection during the year 2007. The usefulness of the palynological observations in the case of PM10 is much lower than that for total suspended particles due to the resolution of absorbed particles, but is still helpful for distinguishing C(3)/C(4) plants that indicate long-distance transport of pollutants. The δ(13)C(PM10) values varied seasonally from-26.9 to-25.1‰. The δ(15)N(PM10) values showed chaotic fluctuations and varied from 5.0 to 13.7‰. Our results indicated that during the heating period, the PM10 particles in Wroc?aw are derived mainly from local home heaters, whereas in the growing period, PM10 particles are derived from local transport and are partially generated by the industrial application of coal combustion outside the city of Wroc?aw.     

Carbon and nitrogen isotope analyses coupled with palynological data of PM10 in Wrocław city (SW Poland) – assessment of anthropogenic impact

We have applied both palynological and carbon and nitrogen isotopic analyses of PM10 (particulate matter with a diameter of 10 μm or less) to trace its origin and to assess the anthropogenic impact for the area under study. The PM10 samples were collected in Wroc?aw (SW Poland) by the Regional Inspectorate for Environment Protection during the year 2007. The usefulness of the palynological observations in the case of PM10 is much lower than that for total suspended particles due to the resolution of absorbed particles, but is still helpful for distinguishing C₃/C₄ plants that indicate long-distance transport of pollutants. The δ¹³C(PM10) values varied seasonally from?26.9 to?25.1‰. The δ¹⁵N(PM10) values showed chaotic fluctuations and varied from 5.0 to 13.7‰. Our results indicated that during the heating period, the PM10 particles in Wroc?aw are derived mainly from local home heaters, whereas in the growing period, PM10 particles are derived from local transport and are partially generated by the industrial application of coal combustion outside the city of Wroc?aw.     

Stable carbon isotopic composition of tree rings from a pine tree from Augustów Wilderness,Poland, as a temperature and local environment conditions indicator

Tree rings can be used as archives of climatic and environmental data with annual resolution. Tree rings widths, maximum late wood density and other parameters as stable composition in tree rings can be used for the reconstruction of past climatic and environmental changes. Stable carbon isotope ratios in tree rings may provide valuable information on past climatic conditions. ¹³C/¹²C ratios of plant organic matter can reflect corresponding ¹³C/¹²C ratio of atmospheric CO₂ during formation of the rings. Investigations of isotopic carbon composition in tree rings from in the ecologically clean the Augustów Wilderness region in the north-eastern part of Poland (22°58′E, 53°51′N) (nowadays a sanctuary) were undertaken. Series of δ¹³C in α-cellulose and in wholewood were acquired. Those measurements constituted a part of more complex investigations of carbon isotope composition in tree rings including the measurements of radiocarbon concentration and tree ring widths. This article presents preliminary results. It is argued that contrary to the tree ring widths and δ¹³C in wholewood that do not reveal significant correlation with temperature, the variation of δ¹³C in the latewood α-cellulose is correlated with combined July and August temperatures.     

Stable carbon isotopic composition of tree rings from a pine tree from Augustów Wilderness, Poland, as a temperature and local environment conditions indicator

Tree rings can be used as archives of climatic and environmental data with annual resolution. Tree rings widths, maximum late wood density and other parameters as stable composition in tree rings can be used for the reconstruction of past climatic and environmental changes. Stable carbon isotope ratios in tree rings may provide valuable information on past climatic conditions. 13C/12C ratios of plant organic matter can reflect corresponding 13C/12C ratio of atmospheric CO2 during formation of the rings. Investigations of isotopic carbon composition in tree rings from in the ecologically clean the Augustów Wilderness region in the north-eastern part of Poland (22 degrees 58'E, 53 degrees 51'N) (nowadays a sanctuary) were undertaken. Series of delta13C in alpha-cellulose and in wholewood were acquired. Those measurements constituted a part of more complex investigations of carbon isotope composition in tree rings including the measurements of radiocarbon concentration and tree ring widths. This article presents preliminary results. It is argued that contrary to the tree ring widths and delta13C in wholewood that do not reveal significant correlation with temperature, the variation of delta13C in the latewood alpha-cellulose is correlated with combined July and August temperatures.     

(Anti-)self-dual homogeneous vacuum gluon field as an origin of confinement and SUL(NF) × SUR(NF) symmetry breaking in QCD

It is shown that an (anti-) self-dual homogeneous vacuum gluon field appears in a natural way within the problem of calculation of the QCD partition function in the form of Euclidean functional integral with periodic boundary conditions. There is no violation of cluster property within this formulation, nor are parity, color and rotational symmetries broken explicitly. The massless limit of the product of the quark masses and condensates, $m_f \left\langle {\bar \psi _f \psi _f } \right\rangle $ , is calculated to all loop orders. This quantity does not vanish and is proportional to the gluon condensate appearing due to the nonzero strength of the vacuum gluon field. We conclude that the gluon condensate can be considered as an order parameter both for confinement and chiral symmetry breaking.     

The origin of copiapite from chlorite pyritic schist (Wieściszowice, Lower Silesia, Poland) in the light of Mössbauer analysis

This work presents the results of the analysis of copiapite, formed from weathering and oxidation of pyrite in pyritic schist from Wie?ciszowice, Lower Silesia (Poland). The pure phase of copiapite was found in secondary minerals after pyrite and identified by optical microscopy, XRD and Mössbauer spectroscopy. In the analyzed copiapite major cations appear to be Fe^2?+? and Fe^3?+?. Some Fe^3?+? is substituted by other cations, mainly Al^3?+?. Al^3?+? probably comes from leaching of chlorite from which hydrated sulphates of iron, mainly szomolnokite, form followed by hydrated sulphates fibroferrite, which is replaced by copiapite.     

Stable carbon isotopes of glucose received from pine tree-rings as bioindicators of local industrial emission of CO2 in Niepołomice Forest (1950–2000)

The mass spectrometric investigations of carbon isotope composition of glucose received from α-cellulose samples derived from Scots pine (Pinus sylvestris L.) growing in Niepo?omice Forest were the main aim of this study. The annual rings covered the time span from 1950 to 2000. α-Cellulose samples were extracted from increment cores of four representative trees, and then acid hydrolysis was performed. The number of sunshine hours, thermal and pluvial conditions of the growing season and in the preceding months had a significant effect on pine. Also non-climatic factors, most likely by industrial pollution signal, have been recorded in the isotopic composition of glucose. The relationship between climatic conditions, carbon dioxide emission and annual tree-rings carbon isotopic composition was analysed, using methods of correlation and response function, and multiple regression function.     

Isotopic fingerprints of the Lake Żabińskie (NE Poland) hydrological system on contemporary carbonates precipitated in the lake

An isotopic monitoring was undertaken in 2012–2014 at Lake ?abińskie (Mazurian Lakeland, NE Poland). The aim was to identify the factors and processes controlling an isotopic composition of the lake water and to explore the mechanism responsible for recording the climatic signal in stable isotope composition of deposited carbonates. δ¹⁸O and δ²H in the precipitation, lake water column, inflows and outflow, δ¹⁸O and δ¹³C in the carbonate fraction of sediments trapped in the water column were recorded with monthly resolution. A relationship between δ¹⁸O and δ²H in local precipitation was used to estimate the local meteoric water line. The dataset obtained for the water enabled to identify the modification of the water’s isotopic composition due to evaporation, connected with seasonal lake water stratification and mixing patterns. Statistically significant correlation coefficients suggest that the δ¹⁸O of the carbonate fraction in the sediment traps depends on the δ¹⁸O of rainfall water and on air temperature. The fractionation coefficient α shows that in summer months the carbonate precipitation process is closest to equilibrium. As expected for an exorheic lake, no significant correlation was observed between δ¹⁸O and δ¹³C in precipitated carbonate.     

Voltammetric behaviors of an emerging pollutant benzotriazole on multiwall carbon nanotubes (MWNTs)—Nafion modified electrode in various pH mediums

The electrochemical behaviors of an emerging pollutant, benzotriazole (BTA), at multiwall carbon nanotubes and Nafion modified glassy carbon electrode (MWNTs-Nafion/GCE) were investigated systematically. The electrochemical reduction of BTA was significantly improved by MWNTs-Nafion compared to bare GCE, ascribed to the excellent adsorption capacity and electrocatalytic activity of MWNTs. BTA presented well-defined reduction peaks only at pH <3.0, suggesting the involvement of lots of protons in the reduction process. Peak potential shifted negatively and peak current decreased significantly with pH increase. BTA showed various UV–Vis absorption spectra in acidic and alkaline mediums. Cathodic peak current increased linearly with square root of sweep rate as well as with the concentration of BTA from 3.0?×?10^?6 to 1.6?×?10^?4 mol L^?1. This suggests a diffusion-controlled and irreversible electrode process. Diffusion coefficient of BTA on MWNTs-Nafion/GCE was obtained as 2.67?×?10^?2 cm² s^?1 with four orders of magnitude larger than that on GCE. MWNTs-Nafion/GCE showed a good selectivity between BTA and O₂ but poor selectivity between BTA and tolyltriazole.     

Young's modulus as a function of composition for an n-type lead–antimony–silver–telluride (LAST) thermoelectric material

For 17 cast lead–antimony–silver–telluride (LAST) thermoelectric specimens (representing 14 different chemical compositions), a combination of Vickers and Knoop microindentation techniques were used to determine the composition-dependent Young's modulus, E, which ranged from 24 to 68?GPa. Following microindentation, independent nanoindentation measurements were also performed on 10 of the 17 specimens. In the literature, for pseudobinary joins in ternary or quaternary compounds (with the compositions A _x B_{1– x} C or A _x B_{1– x} CD, respectively), changes in the Young's modulus have been expressed as quadratic functions of the compositional parameter x. In this study, we extend the quadratic functional form to a paraboloid in four composition variables to describe composition-dependent changes in E for the LAST compounds. Also, the composition-dependent changes in LAST are compared to the trends observed in the literature for E and bulk modulus for systems described by a single compositional variable.     

Structural origin of apparent Fermi surface pockets in angle-resolved photoemission of Bi₂Sr(2-x)La(x)CuO(6+δ)

We observe apparent hole pockets in the Fermi surfaces of single-layer Bi-based cuprate superconductors from angle-resolved photoemission. From detailed low-energy electron diffraction measurements and an analysis of the angle-resolved photoemission polarization dependence, we show that these pockets are not intrinsic but arise from multiple overlapping superstructure replicas of the main and shadow bands. We further demonstrate that the hole pockets reported recently from angle-resolved photoemission [Meng et al., Nature (London) 462, 335 (2009)] have a similar structural origin and are inconsistent with an intrinsic hole pocket associated with the electronic structure of a doped CuO? plane.     

A critical consideration of magnetism and composition of (bcc) Cu precipitates in (bcc) Fe

Atom probe and small-angle neutron scattering (SANS) measurements were carried out in order to investigate the chemical composition of (bcc) Cu precipitates in a (bcc) Fe matrix. The ratio of nuclear and magnetic integrated intensities (R-value) found by SANS is compared to a theoretical model which is based on the chemical composition obtained from the atom probe data. Furthermore, density functional theory calculations were performed to derive the magnetic moment per atom and the lattice parameters of the Cu alloys modeled in terms of supercells. The calculated and measured R-values agree rather well suggesting that Fe atoms are incorporated in the Cu precipitates up to concentrations of about 50 at.%.     

The origin of the enhancement of magnetic properties in Sm2Fe17Nx (0

《Journal of magnetism and magnetic materials》2002,247(1):42-54

On the presence of spectral shortcut in the energy budget of an asymmetric jet–wake flow in a forward-curved centrifugal turbomachine as deduced from SPIV measurements

Viscous dissipation and its contribution to turbulent kinetic energy (TKE) budget are investigated in the asymmetric jet–wake flow of a forward-curved centrifugal turbomachine. Single-plane three-dimensional turbulent data are obtained using stereoscopic particle image velocimetry (SPIV). Viscous dissipation is indirectly estimated from subgrid-scale (SGS) dissipation (SGS energy flux) by filtering velocity field using a top-hat filter. The filter scale should be within the inertial sub-range and this is ensured by spectral analysis of the measured field. Reduction of turbulent energy flux for smaller filter scales plus underestimation of viscous dissipation as compared with other TKE terms both suggest the presence of spectral shortcut. This bypass energy transfer (from intermediate scales towards dissipative scales) works in parallel with direct SGS energy transfer and affects the classical energy cascade. Analysis of TKE budget in the rotor exit region shows significant radial/circumferential variations in the contributing terms. These variations are mainly due to jet–wake–volute interactions, circumferential asymmetry of volute area and expansion of flow toward the fan outlet.     

Increase in the coercivity of an ensemble of (DyPr)–(CoFe)–B microparticles during their dispersion in a polymer matrix

In ensembles of annealed ferrimagnetic alloy (DyPr)–(CoFe)–B microparticles in the free state and fixed in polymer, the coercivity differs more than by an order of magnitude. The contributions of orientation locking of magnetic axes of particles and the dipole magnetic interaction between particles to the coercivity and saturation magnetization field of an ensemble are discussed. In ensembles of unannealed microparticles, the effect of their locking and dispersing in polymer is significantly weaker.     

Decay of amplitude-modulation property of song and an analysis of sounding mechanism in mottled cicade (Gaeana maculata Drury)

I-IntroductionTheamp1itudc-modulationpropcrtyexistsgcnerallyinthesongsofarthropods.Insingingorthoptcraninsccts,suchasmo1c-cricket,1ocust,cricketandkatydid,thesongsproduccdbystridulationsarctypica1andcachwave(thetoothstrike)incarrierwavesisisproducedbythatthescrapcrstrikesateachtoothofthedenticulatedvein(fi1e)t'J.IncicadasoftheHomoptera,thesongsareproduccdbycontractionmovcmentsofthesoundingmusc1etodrivethesoundingmembranewithribstructurestovibrations,andaregeneral1yamplitude-modu1ationpu1sesou…