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    Wyświetlanie 1-29 z 29
    Tytuł:
    The kinetics, thermodynamics and equilibrium study of nickel and lead uptake using corn residues as adsorbent
    Autorzy:
    Tejada-Tovar, Candelaria
    Villabona-Ortíz, Ángel
    Gonzalez-Delgado, Angel Darío
    Powiązania:
    https://bibliotekanauki.pl/articles/1844359.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Technologiczno-Przyrodniczy
    Tematy:
    adsorption
    corn wastes
    heavy metals
    kinetics
    thermodynamics
    Opis:
    Agricultural residues rich in lignocellulosic biomass are low-cost and sustainable adsorbents widely used in water treatment. In the present research, thermodynamics, kinetics, and equilibrium of nickel(II) and lead(II) ion biosorption were studied using a corncob (Zea mays). The experiments were performed in a batch system evaluating the effect of temperature and dose of adsorbent. Langmuir and Freundlich isotherms were used to study the equilibrium. Thermodynamic and kinetic parameters were determined using kinetic models (pseudo-first order, pseudo-second order, Elovich). Biosorbent characteristics were studied by Fourier-transform infrared spectroscopy, Scanning Electron Microscopy and Energy-dispersive X-ray spectroscopy. It was found that the hydroxyl, carboxyl, and phenolic groups are the major contributors to the removal process. Besides, Pb(II) ions form micro-complexes on the surface of the biomaterial while Ni(II) ions form bonds with active centers. It was found that the highest Ni(II) removal yields were achieved at 0.02 g of adsorbent and 70°C, while the highest Pb(II) removal yields were achieved at 0.003 g and 55°C. A maximum Ni(II) adsorption capacity of 3.52 mg∙g–1 (86%) and 13.32 mg∙g–1 (94.3%) for Pb(II) was obtained in 250 and 330 min, respectively. Pseudo-first order and pseudo-second order models best fit experimental data, and Langmuir and Freundlich models well describe the isotherm of the process. Thermodynamic parameters (ΔH0, ΔG0, ΔS0) suggest that the adsorption process of both cations is exothermic, irreversible, and not spontaneous.
    Źródło:
    Journal of Water and Land Development; 2021, 48; 197-204
    1429-7426
    2083-4535
    Pojawia się w:
    Journal of Water and Land Development
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Removal of phenol from wastewater using activated waste tea leaves
    Autorzy:
    Mohsin, K.
    Anwar, R. S.
    Nadeem, F.
    Amir, Y.
    Syed, W. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/778237.pdf
    Data publikacji:
    2013
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    acid activation
    batch study
    biosorption
    equilibrium study
    kinetic study
    Opis:
    This investigation enumerates the treatment of phenol contaminated synthetic wastewater by Activated Waste Tea Leaves (AWTL). Phosphoric acid was used for the modification of waste tea leaves. The effects of initial pH, biosorbent dose, contact time, and initial phenol concentration were studied on the phenol uptake from the synthetic solution. Kinetic modelling was performed using pseudo 1st and 2nd order kinetics. The Langmuir and Freundlich’s Models were employed to interpret the AWTL behaviour at various mass transfer gradients. The results show that the optimum values for pH, biosorbent dose and contact time were 2.2 g/L and 180 minutes, respectively. Pseudo 2nd order kinetic and the Langmuir’s Models best described the kinetic and equilibrium behaviours, respectively.
    Źródło:
    Polish Journal of Chemical Technology; 2013, 15, 2; 1-6
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Equilibrium swelling study of crosslinked chitosan membranes in water, buffer and salt solutions
    Autorzy:
    Gierszewska, Magdalena
    Ostrowska-Czubenko, Jadwiga
    Powiązania:
    https://bibliotekanauki.pl/articles/1034640.pdf
    Data publikacji:
    2016
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan
    crosslinking
    equilibrium swelling
    membranes
    Opis:
    Physically crosslinked membranes were prepared by treating chitosan (Ch) with pentasodium tripolyphosphate (TPP) at different reaction conditions. The equilibrium swelling ratio, Seq, of Ch/TPP membranes in water, buffer and salt solutions at 37 C were determined. The experimental data indicated, that Seq depended on pH of buffer solution and type and concentration of salt solution. Swelling capacity in water depended on the content of TPP ions in the membrane and crosslinking density
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2016, 21; 55-62
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microstructural and Equilibrium Adsorption Study of the System of Waste Foundry Molding Sand/Cu (II) Ions
    Autorzy:
    Strkalj, A.
    Glavas, Z.
    Slokar, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/354568.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    waste foundry molding sand
    Cu (II) ions
    adsorption
    SEM/EDS analysis
    Opis:
    This paper deals with the waste foundry molding sand which originally comes from the casting production. Adsorption of Cu (II) ions on the waste foundry molding sand was studied. Experimental data were processed using adsorption isotherms. Obtained results show that the experimental data are best described by the Langmuir isotherm. The following adsorption capacities are obtained: 7.153 mg/g to 293 K, 8.403 mg/g at 333 K and 9.208 mg/g at 343 K. The kinetics and thermodynamics of the process were analysed. The obtained results indicate that the adsorption process takes place according to the pseudo second order kinetic model with the following constants: 0.438 g/mg min at 293 K, 0.550 g/mg min at 333 K and 1.872 g/mg min at 343 K. The following values of ΔG° were obtained: − 95.49 J/mol at 293 K, − 736.99 J/mol at 333 K and − 1183.46 J/mol at 343 K. The value of ΔH° is − 4.16 kJ/mol and the value of ΔS° is 15.17 J/molK. These results were confirmed by microscopic examinations. The results indicate that the adsorption process of Cu (II) ions on waste foundry molding sand is possible. Results of microscopic examinations show the homogeneity of the surface, which is proof of the chemisorption. Cu (II) ions on the surface of the waste foundry molding sand were detected after adsorption by EDS analysis, which proves the existence of the adsorption process.
    Źródło:
    Archives of Metallurgy and Materials; 2016, 61, 4; 1805-1812
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Protein-cationic detergent interaction. Equilibrium dialysis study of the interaction of bovine serum albumin and other proteins with alkyl pyridinium bromide
    Autorzy:
    Wasylewski, Zygmunt
    Powiązania:
    https://bibliotekanauki.pl/articles/1046210.pdf
    Data publikacji:
    1979
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Źródło:
    Acta Biochimica Polonica; 1979, 26, 3; 195-203
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Equilibrium, kinetics and thermodynamic study of the adsorptive removal of methylene blue from industrial wastewater by white cedar sawdust
    Autorzy:
    Gardazi, Syed Mubashar H.
    Shah, Jehanzeb Ali
    Ashfaq, Tayyab
    Sherazi, Tauqir A.
    Ali, Muhammad Arif
    Pervez, Arshid
    Rashid, Naim
    Iqbal, Javed
    Amin, Bilal Ahmad Zafar
    Bilal, Muhammad
    Powiązania:
    https://bibliotekanauki.pl/articles/207373.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    methylene blue
    industrial wastewater
    white cedar sawdust
    WCS
    dye adsorption
    błękit metylenowy
    ścieki przemysłowe
    trociny białego cedru
    adsorpcja barwników
    Opis:
    The study evaluated the adsorption potential of white cedar sawdust (WCS) for dye removal. WCS was chosen from five preferred, abundant waste biomasses from Pakistan. Various parameters such as contact time, adsorbent dose, dye concentration, pH, and particle size were optimized for methylene blue (MB) dye adsorption. The adsorbent was characterized by FTIR, SEM, EDX and BET analyses. The surface area of the adsorbent was 1.43 m2·g-1 and pore volume was 0.000687 cm3·g-1. The adsorption data best fitted the isotherm models of Langmuir, Temkin, Dubinin–Radushkevich, and Freundlich. The maximum experimental adsorption capacity obtained was 55.15 mg·g-1, which was in close agreement to the calculated adsorption capacity. Fitness of the pseudo-second order kinetics suggested chemisorption as the rate-limiting step. Thermodynamic study for adsorption was carried out to evaluate the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). The negative values ΔG° at the examined temperature range confirmed the spontaneous adsorption of MB onto WCS.
    Źródło:
    Environment Protection Engineering; 2019, 45, 3; 5-22
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Batch removal of Pb (ΙΙ) ions from aqueous medium using gamma-Al2O3 nanoparticles/ethyl cellulose adsorbent fabricated via electrospinning method: An equilibrium isotherm and characterization study
    Autorzy:
    Pouya, E. S.
    Fatoorehchi, H.
    Foroughi-Dahr, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/778139.pdf
    Data publikacji:
    2018
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    Adsorption
    Pb (II) ions
    Ethyl cellulose
    Gamma-Al2O3 nanoparticles
    Electrospinning
    Opis:
    The aim of the present work is to study the efficiency of a biocompatible polymer-based adsorbent for the removal of Pb (II) ions whose devastating effects on people’s health is a matter of great concern from aqueous solution. In this study, ethyl cellulose and gamma-Al2 O<3  nanoparticles/ethyl cellulose electrospun adsorbents were prepared for the batch removal of Pb (II) ions from aqueous solution. Both samples were characterized using contact angle analysis, N2 adsorption/desorption technique, FT-IR and SEM. The Freundlich model (R-square = 0.935 and RMSD (%) = 6.659) and the Dubinin-Radushkevich model (R-square = 0.944 and RMSD (%) = 6.145) were found to be more reliable in predicting the experimental data from the adsorption of Pb (II) ions onto the electrospun gamma-Al2 O<3  nanoparticles/ethyl cellulose than the Langmuir model (R-square = 0.685 and RMSD (%) = 14.61) and also the Temkin model (R-square = 0.695 and RMSD (%) = 14.38).
    Źródło:
    Polish Journal of Chemical Technology; 2018, 20, 2; 32-39
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermodynamic study of phase equilibrium of superionic alloys of Ag3SBr1-xClx system in the concentration range 0.0–0.4 and temperature range 370–395 K
    Autorzy:
    Moroz, M. V.
    Prokhorenko, M. V.
    Prokhorenko, S. V.
    Reshetnyak, O.V.
    Powiązania:
    https://bibliotekanauki.pl/articles/240425.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    phase equilibrium
    superionic alloys
    thermodynamic properties
    Gibbs energy
    EMF method
    równowaga fazowa
    właściwości termodynamiczne
    energia Gibbsa
    metoda EMF
    Opis:
    Thermodynamic assessment of the phase stability of the solid solutions of superionic alloys of the Ag3SBr1-xClx (I) system in the concentration range 0 ≤ x ≤ 0.4 and temperature range 370–395 K was performed. Partial functions of silver in the alloys of solid solution were used as the thermodynamic parameters. The values of partial thermodynamic functions were obtained with the use of the electromotive force method. Potential-forming processes were performed in electrochemical cells. Linear dependence of the electromotive force of cells on temperature was used to calculate the partial thermodynamic functions of silver in the alloys. The serpentine-like shape of the thermodynamic functions in the concentration range 0–4 is an evidence of the metastable state of solid solution. The equilibrium phase state of the alloys is predicted to feature the formation of the intermediate phase Ag3SBr0.76Cl0.24, and the solubility gap of the solid solution ranges of Ag3SBr0.76Cl0.24 and Ag3SBr.
    Źródło:
    Archives of Thermodynamics; 2017, 38, 1; 27-38
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of continuous phase transition with Toom cellular automata
    Autorzy:
    Makowiec, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/1941716.pdf
    Data publikacji:
    2000
    Wydawca:
    Politechnika Gdańska
    Tematy:
    equilibrium lattice model
    equilibrium lattice systems
    critical components
    Gibbsian measures
    Ising model
    Opis:
    The heuristic proof, based on computer simulation investigations, is presented that though stationary Toom cellular automata exhibit many features which are characteristic for an equilibrium system (e.g. rapid change in the order parameter, when noise is fine tuned, or slow decay of the two point correlation function), the stationary state is not Gibbsian. It means that it is impossible to define energy on the microscopic level in such a way that the dynamic system becomes representative of some equilibrium lattice model. Moreover, properties on the coarse-grained level: fluctuations, seem to be distinct from the corresponding ones of the Ising model.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 1; 19-31
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical study of an unsteady non-premixed flame in a porous medium based on the thermal equilibrium model
    Autorzy:
    Pakdee, Watit
    Sakkarangkoon, Thammasathit
    Powiązania:
    https://bibliotekanauki.pl/articles/1839676.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    porous combustion
    non-premixed combustion
    local thermal equilibrium
    pseudohomogeneous
    numerical model
    Opis:
    The present research numerically investigates the non-premixed combustion of CH4 in a porous medium. The mathematical model proposed consists of conservation of mass, momentum, energy, and species equations. The discretized equations are integrated according to the third - order Runge - Kutta method. A porous medium is defined as a pseudohomogeneous medium. The proposed unsteady model is successfully validated with the published study. The model is able to describe physical behaviors of a non-premixed flame. The porous structure made of SiC gives higher temperature than when Al2O3 is used since SiC has higher thermal conductivity and lower heat capacity.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2021, 59, 3; 401-412
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of uni-univalent H+/K+ and uni-bivalent H+/Mg2+ ion exchange reactions using nuclear grade resin Indion-223
    Autorzy:
    Singare, P. U.
    Mohammed, A. K. L.
    Dixit, N. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/411848.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    ion exchange equilibrium
    nuclear grade resins
    cation exchange
    enthalpy change
    equilibrium constant
    Indion-223
    Opis:
    In the present paper the uni-univalent and uni-bivalent ion exchange reactions were investigated using nuclear grade anion exchange resin Indion-223 in H+ form. For both H+/K+ uni-univalet ion exchange reactions and H+/Mg2+ uni-bivalet ion exchange reactions, the equilibrium constant K values increases from 0.01710 to 0.02374 and from 0.000177 to 0.000333 respectively as the reaction temperature rises from 35.0 °C to 45.0 °C. The increase in K values with temperature suggest endothermic ion exchange reactions having the enthalpy change values of 22.72 and 51.46 kJ/ mol respectively. The results of such studies will help in selection of suitable ion exchange resins in order to bring about efficient separation of different ionic species present in the waste water effluents released from nuclear as well as chemical process industries.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 14, 2; 231-239
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of the stability of methane hydrates in normal conditions
    Autorzy:
    Pavlenko, A.
    Koshlak, V.
    Vytyaz, O.
    Powiązania:
    https://bibliotekanauki.pl/articles/298759.pdf
    Data publikacji:
    2014
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    storage of gas
    gas hydrates
    hydrate błock
    thermal conductivity
    forcibly preservation
    equilibrium conditions
    Opis:
    The problems of accumulation, transport and storage of gases and gas mixtures exist in many cases. Often the existent technologies appear ineffective for transporting his with pipelines, as condensate or compressed gas. Therefore, the transportation and storage of gas in hydrate form can be an alternative to traditional technologies. Preservation of gas hydrate blocks can store them for some time at the no equilibrium conditions. The thermodynamic parameters of forcibly conservation of gas hydrate blocks theoretically are determined and experimentally verified.
    Źródło:
    AGH Drilling, Oil, Gas; 2014, 31, 4; 495-505
    2299-4157
    2300-7052
    Pojawia się w:
    AGH Drilling, Oil, Gas
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on buildup of fine weakly magnetic minerals on matrices in high gradient magnetic separation
    Autorzy:
    Zheng, X.
    Wang, Y.
    Lu, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/109662.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    particle buildup
    force equilibrium
    magnetic matrices
    magnetic separation
    Opis:
    Buildup of magnetic mineral particles on matrices determines the saturated deposit volume of minerals, which is of great importance in the high gradient magnetic separation (HGMS) systems. In this paper buildup of fine weakly magnetic minerals on the matrix is studied with a force equilibrium model. Elaborate rules of particle buildup on the matrix are presented. An imaginary sector ring is used to approximately quantify the volume of saturated particle buildup. The influence of the particle size, magnetic induction, fluid viscosity and velocity as well as matrix size on saturated particle buildup is investigated and discussed. With the same matrix size, the saturated buildup volume decreases with the decrease of the particle size, applied magnetic induction and increase of the fluid viscosity and velocity. The saturated buildup volume normalized by the matrix volume, and the ratio of particle deposit volume to the matrix volume (Vd/Vm) decreases with the increase of the matrix size. Under the same matrices packing fraction, the total mineral deposit volume, when adopting small size matrices, is larger than that when adopting large size matrices. Only small size matrices can be used for recovery of minerals in size of several micrometers. Based on performed analyses, the ore feeding time in a cycle for a cyclic HGMS system and the rotation speed of the swivel for a continuous HGMS system under different circumstances are also discussed.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 1; 94-109
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of the Magnetic Water Treatment Mechanism
    Autorzy:
    Vaskina, Iryna
    Roi, Ihor
    Plyatsuk, Leonid
    Vaskin, Roman
    Yakhnenko, Olena
    Powiązania:
    https://bibliotekanauki.pl/articles/123611.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    wastewater
    aqueous solutions
    water isomer
    magnetic induction
    non-equilibrium system
    librational fluctuation
    Opis:
    The main problem of widespread introduction of magnetic water treatment (MWT) in the processes of water and wastewater treatment is the lack of modern research aimed at studying the mechanisms of MWT effects, in particular the influence on the physicochemical properties of aqueous solutions. This study explains the effect of MWT taking into account the physical and chemical properties of aqueous solutions due to the presence of the quantum differences in water molecules. All of the MWT effects are related to the change in the physicochemical properties of aqueous solutions. It is due to the presence of two types of water molecule isomers and their librational oscillations. The result of MWT is a violation of the synchronism of para-isomers vibrations, with the subsequent destruction of ice-like structures due to the receiving of energy from collisions with other water molecules (ortho-isomers). One of the most important MWT effects includes the change in the nature and speed of the physicochemical processes in aqueous solutions by increasing the number of more physically and chemically active ortho-isomers. The MWT parameters specified in the work allow explaining the nature of most MWT effects and require developing the scientific and methodological principles for the implementation of the MWT process and mathematical modeling of the MWT process in the water and wastewater treatment. It can be used in the design of the MWT devices taking into account the constructive and mode parameters of MWT devices.
    Źródło:
    Journal of Ecological Engineering; 2020, 21, 2; 251-260
    2299-8993
    Pojawia się w:
    Journal of Ecological Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An experimental study on drying characteristics and kinetics of figs (Ficus carica)
    Autorzy:
    Sarvestani, F. Sabet
    Rahimi, A.
    Hatamipour, M. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/779372.pdf
    Data publikacji:
    2014
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    drying kinetics
    figs
    effective diffusivity
    equilibrium moisture content
    drying
    Opis:
    In this study, the thin-layer drying characteristics of Figs (Ficus carica) are investigated in a pilot scale forced convective dryer. Experiments carried out under various operating conditions including air temperature (40, 50, 60, 70°C), air velocity (0.65, 2.1, 3.45, 4.85 m/s) and air humidity (0.005, 0.010, 0.015 kg/kg) and the effects of these operating conditions on the drying kinetics and the drying time determined. The obtained kinetics data are fitted into a conceptually developed model. The equilibrium moisture content of the dried figs is determined at different values of temperature and relative humidity of air. The values of effective moisture diffusivity (Deff) are obtained from the Fick’s second law and a temperature-dependent relation is proposed for this parameter.
    Źródło:
    Polish Journal of Chemical Technology; 2014, 16, 4; 60-65
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Porównawcze badania krwi tętniczej, włośniczkowej, żylnej arterializowanej i żylnej w określaniu równowagi kwasowo-zasadowej
    The comparison of arterial, capilar, arterialised-venous and venous blood in study of acid-base equilibrium
    Autorzy:
    Adamiak, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2189776.pdf
    Data publikacji:
    1970
    Wydawca:
    Polskie Towarzystwo Diagnostyki Laboratoryjnej
    Źródło:
    Diagnostyka Laboratoryjna; 1970, 06, 2; 127-132
    0867-4043
    Pojawia się w:
    Diagnostyka Laboratoryjna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A game theoretical study of generalised trust and reciprocation in Poland. I. Theory and experimental design
    Autorzy:
    Markowska-Przybyła, U.
    Ramsey, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/406367.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    experimental game theory
    Bayesian equilibrium
    trust
    reciprocation
    eksperymentalna teoria gier
    równowaga Bayesa
    zaufanie
    wzajemność
    Opis:
    Although studies using experimental game theory have been carried out in various countries, no such major study has occurred in Poland. The study described here aims to investigate generalised trust and reciprocation among Polish students. In the literature, these traits are seen to be positively correlated with economic growth. Poland is regarded as the most successful post-soviet bloc country in transforming to a market economy but the level of generalised trust compared to other postcommunist countries is reported to be low. This study aims to see to what degree this reported level of generalised trust is visible amongst young Poles via experimental game theory, along with a questionnaire. The three games to be played have been described. Bayesian equilibria illustrating behaviour observed in previous studies have been derived for two of these games and the experimental procedure has been described.
    Źródło:
    Operations Research and Decisions; 2014, 24, 3; 59-76
    2081-8858
    2391-6060
    Pojawia się w:
    Operations Research and Decisions
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Apparatus to study volumetric properties of the gas hydrates
    Autorzy:
    Lorenc, M.
    Warowny, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/298898.pdf
    Data publikacji:
    2012
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    hydrate
    hydratation
    methane
    hydrogen sulfide
    separation
    desulfurization
    natural gas
    laboratory apparatus
    nucleation
    phase equilibrium
    dissociation
    uwadnianie
    metan
    aparatura laboratoryjna
    siarkowodór
    gaz ziemny
    Opis:
    A new pVT apparatus was built on Department of Drilling, Oil and Gas at AGH University of Science and Technology, which was sponsored by the Polish Oil and Gas Company. The apparatus was adjusted to measurement of the proprieties of the gas hydrates. On the schematic diagram of this apparatus, methodological solutions of the equipment were compared to different of this kind literature apparatuses. Among others innovatory elements of the present apparatus some of them should be counted: method of the changes of volume or automatic system (arrangement) to taking the sample with supported nafion drying. The first step of the experimental study is desulfurization of the natural, by using process of the hydrates formation in gas mixture.
    Źródło:
    AGH Drilling, Oil, Gas; 2012, 29, 3; 419-430
    2299-4157
    2300-7052
    Pojawia się w:
    AGH Drilling, Oil, Gas
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on Halide Ions Selectivity of Industrial Grade Anion Exchange Resin Auchlite A-378
    Autorzy:
    Singare, P. U.
    Patange, A. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/412220.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    selectivity
    ion exchange reactions
    halide ions
    industrial grade resins
    anion exchange resins
    enthalpy
    equilibrium constant
    Auchlite A-378
    Opis:
    The thermodynamic approach was applied to predict the trend selectivity of industrial grade anion exchange resin Auchlite A-378 in chloride form towards iodide and bromide ions in the solution. The study was conducted by performing the Clˉ/Iˉ and Clˉ/Brˉ uni-univalent ion exchange reactions under gradually increasing temperature conditions. The thermodynamic equilibrium constants K values were used to calculate the enthalpies of the two uni-univalent ion exchange reactions. It was observed that the K values for Clˉ/Iˉ ion exchange reaction were higher than Clˉ/Brˉ exchange reaction under identical experimental conditions. Also the enthalpy values for the two uni-univalent ion exchange reactions were calculated as -39.51 and -18.38 kJ/mol respectively. The high K and low enthalpy values obtained for Clˉ/Iˉ ion exchange reaction is responsible for higher selectivity of the resin towards iodide ions as compared to that towards bromide ions, when both the ions are present in the same solution.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 11, 1; 44-50
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on Halide Ions Selectivity of Nuclear Grade Anion Exchange Resin Auchlite ARA-9366
    Autorzy:
    Singare, P. U.
    Patange, A. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/412305.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    selectivity
    ion exchange reactions
    halide ions
    nuclear grade resins
    anion exchange resins
    enthalpy
    equilibrium constant
    Auchlite ARA-9366
    Opis:
    The selectivity behaviour of nuclear grade anion exchange resin Auchlite ARA-9366 in chloride form towards iodide and bromide ions in the solution was studied. The trend in selectivity of the resin was predicted on the basis of thermodynamics of Clˉ/Iˉ and Clˉ/Brˉ uni-univalent ion exchange reactions. It was observed that the equilibrium constants K values for Clˉ/Iˉ ion exchange reaction were higher than that calculated for Clˉ/Brˉ exchange under identical experimental conditions. Also the enthalpy values for the two uni-univalent ion exchange reactions were calculated as -47.87 and -36.14 kJ/mol respectively. The high K and low enthalpy values obtained for Clˉ/Iˉ ion exchange reaction as compared to that obtained during Clˉ/Brˉ exchange supports higher selectivity of the resin towards iodide ions as compared to that towards bromide ions, when both the ions are present in the same solution.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 11, 1; 67-73
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on preferential selectivity of nuclear grade resin Indion-223 towards some bivalent ions
    Autorzy:
    Singare, P. U.
    Mohammed, A. L. K.
    Dixit, N. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/412085.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    bivalent exchange reactions
    nuclear grade resins
    cation exchange
    reaction thermodynamics
    enthalpy change
    ionic selectivity
    equilibrium constant
    Indion-223
    Opis:
    In the present paper attempts are made to understand the selectivity of nuclear grade cation exchange resin Indion-223 in H+ form towards Ca2+ and Mg2+ bivalent ions in the solution based on thermodynamic concept. It was observed that with rise in temperature the equilibrium constant K values for H+/Ca2+ uni-bivalet ion exchange reactions increases from 0.000397 to 0.000639. Similarly for H+/Mg2+ uni-bivalet ion exchange reactions the equilibrium constant K values increases from 0.000177 to 0.000333. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 38.92 and 51.46 kJ/ mol respectively. The difference in K values and enthalpy values were used to predict the selectivity behaviour of the resin towards the Ca2+ and Mg2+ bivalent ions in the solution. The thermodynamic concept of the present study can be applied to understand the selectivity behaviour of different nuclear as well as non-nuclear grade resins towards wide range of ionic species present in the exchanging liquid medium.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 15; 11-21
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of addition of carbon nanotubes on rheological properties of selected liquid lubricants - a computer simulation study
    Autorzy:
    Chopra, Anjali
    Winczewski, Szymon
    Powiązania:
    https://bibliotekanauki.pl/articles/1954594.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Gdańska
    Tematy:
    nanotechnology
    tribology
    lubricants
    rheology
    propylene glycol
    carbon nanotubes
    non-equilibrium molecular dynamics
    nanotechnologia
    tribologia
    smary
    reologia
    glikol propylenowy
    nanorurki
    nierównowagowa dynamika molekularna
    Opis:
    This work is motivated by the improvement of anti-friction properties of lubricants by addition of CNTs proved experimentally in literature. In particular, a methodology is developed to compute the shear viscosity of liquid lubricants (Propylene Glycol) based on Molecular Dynamics simulation. Non-Equilibrium molecular dynamics (NEMD) approach is used with a reactive force field ReaxFF implemented in LAMMPS. The simulations are performed using the canonical (NVT) ensemble with the so-called SLLOD algorithm. Couette flow is imposed on the system by using Lees-Edwards periodic boundary conditions. Suitable parameters such as simulation time and imposed shear velocity are obtained. Using these parameters, the influence of addition of 27 wt% CNTs to Propylene Glycol on its viscosity is analyzed. Results show that 3.2 million time-steps with a 0.1 fs time-step size is not sufficient for the system to reach equilibrium state for such calculations. With the available computational resources, a shear velocity of 5 × 10−5 Å/fs was observed to give viscosity value with approximately 43% error as compared to the experimental value. Moreover, the lubricant exhibited a shear thinning behaviour with increasing shear rates. CNTs enhanced the lubricant's viscosity by 100-190% depending upon the averaging method used for calculation.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2020, 24, 4; 345-388
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ion-exchange reaction thermodynamics to study the selectivity behaviour of nuclear and non-nuclear grade anion exchange resins
    Autorzy:
    Singare, P. U.
    Patange, A. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/412083.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    ionic selectivity
    uni-univalent exchange
    thermodynamic equilibrium constant
    enthalpy
    nuclear grade ion exchange resin
    Auchlite ARA-9366
    Auchlite A-378
    Opis:
    In the present investigation, attempts were made to understand the difference in bromide ion selectivity of the two closely related anion exchange resins Auchlite ARA-9366 and Auchlite A-378 in chloride form. The selectivity difference was predicted based on the thermodynamic equilibrium constants and enthalpy values of Clˉ/Brˉ ion exchange reactions performed by using the two resins. During Clˉ/Brˉ exchange reactions, with rise in temperature from 30.0 °C to 45.0 °C, the equilibrium constant (K) values were observed to decreases from 8.15x10-2 to 6.06x10-2 for Auchlite ARA-9366 resins and from 2.16x10-2 to 1.10x10-2 for Auchlite A-378 resins. The decrease in K values with rise in temperature, indicate exothermic ion exchange reactions having enthalpy values of -36.14 and -18.38 kJ/mol respectively. The high K and low enthalpy values obtained for Auchlite ARA-9366 resins indicate their greater selectivity for the bromide ions in the solution as compared to Auchlite A-378 resins.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 6; 8-15
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermodynamic study to evaluate the selectivity behaviour of nuclear grade resin Indion-223 towards some univalent ions
    Autorzy:
    Singare, P. U.
    Mohammed, A. L. K.
    Dixit, N. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/412486.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    uni-univalent ion exchange reactions
    ionic selectivity
    nuclear grade resins
    cation exchangers
    enthalpy change
    equilibrium constant
    Indion-223
    Opis:
    The present paper deals with the application of thermodynamic concept in understanding the preferential selectivity of nuclear grade anion exchange resin Indion-223 in H+ form towards Na+ and K+ ions in the solution. In the study it was observed that the equilibrium constants K values for H+/Na+ and H+/K+ uni-univalet ion exchange reactions increases from 0.01389 to 0.01855 and from 0.01710 to 0.02374 respectively as the temperature increases from 35.0 °C to 45.0 °C. The increase in K values with rise in temperature suggests endothermic ion exchange reactions having the enthalpy change values of 25.55 and 22.72 kJ/ mol respectively. Based on difference in K values and enthalpy values for the two uni-univalent ion exchange reactions, the preferential selectivity of the resin for the univalent ions in the solution was predicted. From the results of present study, it appears that the experimental technique used here can be applied further to understand the ionic selectivity of different industrial grade ion exchange resins. It is expected that such studies will provide valuable information in order to decide about the selection of those resins for efficient separation of various ionic species present in the industrial waste water effluents.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 15; 22-29
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparative study of uni-univalent H⁺/Na⁺ and uni-bivalent H⁺/Ca²⁺ ion exchange reactions using nuclear grade resin Indion-223
    Autorzy:
    Singare, P. U.
    Mohammed, A. L. K.
    Dixit, N. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/411747.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    ion exchange reactions
    nuclear grade resins
    cation exchange resins
    enthalpy
    equilibrium constant
    Indion-223
    Opis:
    The present paper deals with the ion exchange equilibrium studies of uni-univalent and uni-bivalent ion exchange reactions using nuclear grade anion exchange resin Indion-223 in H⁺ form towards Na⁺ and Ca²⁺ ions in the solution. It was observed that with rise in temperature the equilibrium constants K values for H⁺/Na⁺ uni-univalet ion exchange reaction increases from 0.01389 to 0.01855. Similarly for H⁺/Ca²⁺ uni-bivalet ion exchange reaction the equilibrium constants K values increases from 0.000397 to 0.000639. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 25.55 and 38.92 kJ/ mol respectively.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 14, 2; 127-135
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of Stress Concentration on the Contour of Underground Mine Workings
    Badanie koncentracji naprężeń na konturze wyrobisk kopalni podziemnych
    Autorzy:
    Pysmennyi, Serhii
    Chukharev, Serhii
    Peremetchy, Andrii
    Fedorenko, Serhii
    Matsui, Anatolii
    Powiązania:
    https://bibliotekanauki.pl/articles/2200991.pdf
    Data publikacji:
    2023
    Wydawca:
    Polskie Towarzystwo Przeróbki Kopalin
    Tematy:
    stress
    working
    vault of stable equilibrium
    stability
    ultimate strength
    rocks
    naprężenie
    praca
    sklepienie równowagi stabilnej
    ciśnienie
    stabilność
    wytrzymałość graniczna
    skały
    Opis:
    Kryvyi Rih iron ore basin consists of complex structured ore deposits and is developed by the underground method at depths of over 1000 m. The underground method is used to mine reserves of rich iron ores with a useful component content of more than 59% applying bulk ore and rock caving systems. This leads to significant changes in the stress state of the rock massif. During underground operations, mine workings are strained and in some cases destructed. As a result, enterprises are constantly increasing operating costs for maintaining mine workings, which adversely impacts the cost of production. Industrial research results demonstrate that in most cases workings fail in their upper part which is vaulted in shape. Available methods for determining the state of rocks around mine workings do not fully take into account physical and mechanical properties of the rocks in which the working is located. The developed technique allows determining not only the destructive pressure impacting the workings, but also the angle at which the destructive force acts. This technique differs from the available ones in taking into account not only mining and geological characteristics of the deposit, but also most factors of physical and mechanical properties of rocks. This technique helps to choose a rational place for driving mine workings at the stage of design, thus avoiding significant additional cost for their maintenance.
    W kopalni Krzywy Róg występują złoża rudy o złożonej strukturze, wydobywane metodą podziemną z głębokości ponad 1000 m. Stosując systemy zawałowe eksploatuje się złoża bogatych rud żelaza o zawartości składników użytecznych powyżej 59%. Prowadzi to do znacznych zmian stanu naprężeń masywu skalnego. Podczas prac podziemnych wyrobiska kopalniane podlegają naprężęniom, a w niektórych przypadkach ulegają zniszczeniu. W efekcie przedsiębiorstwa stale podwyższają koszty eksploatacji wyrobisk górniczych, co niekorzystnie wpływa na koszty produkcji. Wyniki badań przemysłowych wskazują, że w większości przypadków wyrobiska zawodzą w swojej górnej części. Dostępne metody określania stanu skał wokół wyrobisk górniczych nie uwzględniają w pełni właściwości fizycznych i mechanicznych skał, w których znajduje się wyrobisko. Opracowana technika pozwala na określenie nie tylko ciśnienia destrukcyjnego działającego na wyrobiska, ale również kąta działania siły destrukcyjnej. Technika ta rożni się od dostępnych tym, że uwzględnia nie tylko cechy górniczo-geologiczne złoża, ale także większość czynników właściwości fizykomechanicznych skał. Technika ta pozwala już na etapie projektowania na dobór racjonalnych miejsc prowadzenia wyrobisk górniczych, unikając w ten sposób znacznych dodatkowych kosztów ich utrzymania.
    Źródło:
    Inżynieria Mineralna; 2023, 1; 69--78
    1640-4920
    Pojawia się w:
    Inżynieria Mineralna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Factors affecting water quality in degraded sewage receivers - case study of the phosphorus dynamics in the Ner River
    Kształtowanie jakości wody w zdegradowanych odbiornikach ścieków na przykładzie zawartości fosforu w rzece Ner
    Autorzy:
    Mosiej, J.
    Komorowski, H.
    Karczmarczyk, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/293387.pdf
    Data publikacji:
    2007
    Wydawca:
    Instytut Technologiczno-Przyrodniczy
    Tematy:
    odbiornik ścieków
    osady denne
    ekultywacja
    stężenie równowagi fosforu
    uwalnianie fosforu
    equilibrium phosphate concentration (EPCo)
    phosphorus release
    reclamation
    sediments
    sewage receiver
    Opis:
    No adequate reaction has been observed of the decreased contaminant loads discharged by Łódź, particularly the loads of phosphorus, on its concentration in the Ner River . That's why the impact of sediment on phosphorus content in the water was evaluated. Not only was the amount of phosphorus taken under consideration but also the equilibrium phosphate concentration (EPCo). The meaning of EPCo is that any phosphate concentration in the water below this value will lead to phosphorus release from sediments. Performed study shows that in the Puczniew cross-section EPCo is higher then phosphorus concentration in water, thus with mean concentration of PO4 equal to 9.5 mg PO4 · dm-³ phosphorus could be released from sediments. This concentration in Lutomiersk cross-section, however, equals 1.2 mg PO4 · dm-³.
    Rzeka Ner, mimo niewielkiego przepływu wody, wprowadza corocznie do Warty relatywnie duży ładunek zanieczyszczeń. Średni roczny przepływ Neru w analizowanym okresie wynosił ok. 10% przepływu Warty poniżej jego ujścia (ppk Koło), a udział ładunków fosforu wynosił 37%. Stwierdzono brak odpowiedniej reakcji na zmniejszanie się ładunku fosforu odprowadzanego przez Łódź na jego zawartość w wodach Neru. Do 2000 r. ładunek fosforu w ściekach odprowadzanych do rzeki był większy od jego ładunku w profilu zamykającym Chełmno, co może świadczyć o procesach samooczyszczania. Jednak od 2001 r., po dalszym zmniejszeniu ładunku zanieczyszczeń w ściekach, ich ładunek w profilu zamykającym Chełmno jest większy od ładunku zawartego w ściekach. W warunkach małego stężenia fosforu w ściekach (poniżej 4 g·m-³) odprowadzanych z oczyszczalni, przy ujściu rzeki Ner nie obserwuje się odpowiedniego polepszenia jakości wody w profilu Chełmno. Mimo dalszego zmniejszenia zawartości fosforu w ściekach w latach 2002-2004, stężenie w ppk Chełmno nie spada poniżej 0,5 g·m-³, a w 2004 r. nawet zwiększa się do 1,1 g·m-³. Na podstawie wyników badań własnych dokonano oceny wpływu osadów dennych na zawartość fosforu w wodach rzeki Ner. Określono nie tylko zawartość fosforu w osadzie, ale również stężenie w stanie równowagi fosforanowej. Oznacza to, że każde stężenie fosforanów w rzece poniżej tej wartości będzie powodować ich uwalnianie z osadu. Z badań wynika, że w przekroju Puczniew stężenie w stanie równowagi jest większe od stężenia fosforu w wodzie i wynosi 9,5 mg P-PO4 · dm-³, co oznacza, że gdy stężenie w wodzie będzie miało mniejszą wartość, fosfor będzie uwalniał się z osadu. Stężenie w stanie równowagi w przekroju Lutomiersk wynosi 1,2 mg PO4 · dm-³.
    Źródło:
    Journal of Water and Land Development; 2007, 11; 103-116
    1429-7426
    2083-4535
    Pojawia się w:
    Journal of Water and Land Development
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Struktura i dynamika wielogeneracyjnych starodrzewów sosnowych występujących w obszarach ochrony ścisłej Kaliszki i Sieraków w Kampinoskim Parku Narodowym. Część 2. Procesy zamierania i dorastania oraz ich wpływ na rozkład grubości drzew
    Structure and dynamics of uneven−aged, Scots pine−dominated, old−growth stands in Kaliszki and Sieraków strict reserves in Kampinos National Park. Part 2. Tree mortality and recruitment processes and their effects on tree diameter distributions
    Autorzy:
    Brzeziecki, B.
    Zajączkowski, J.
    Olszewski, A.
    Bolibok, L.
    Andrzejczyk, T.
    Bielak, K.
    Buraczyk, W.
    Drozdowski, S.
    Gawron, L.
    Jastrzębowski, S.
    Szeligowski, H.
    Żybura, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/979128.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    demographic non−equilibrium
    diameter structure
    long−term study
    old−growth forest
    permanent study
    plot
    scots pine
    strict protection
    Opis:
    Two fundamental demographic processes (tree recruitment and mortality) are analyzed for forest stands growing on permanent study plots located in strictly protected Scots pine−dominated, old−growth stands of Kampinos National Park (central Poland). The major implications of the observed demographic trends for the general shape of tree size distributions are determined, as well. During the past ca 30 years, in the stands sampled, there was a pronounced lack of balance between mortality and recruitment processes. Mortality rate was eight times higher than recruitment rate. Eventually, there was a net significant decline in population density, observed for all major tree species, including Scots pine, pedunculate oak, silver and downy birch, and black alder. As mortality processes affected mainly smaller trees, there was also a significant deterioration of the general demographic status of most important tree species. This effect was shown by the change of the overall shape of diameter distributions over the study period: from reverse J−shaped to flat curves running nearly parallel to X−axis. The values of recruitment rates were markedly lower, and the values of mortality rates – significantly higher, than analogous values characterizing comparable forests (e.g., those obtained for the natural stands of Białowieża National Park). Low recruitment rates, as obtained for Kampinos stands, suggest that presently, in the local, Scots pine−dominated, old−growth stands, the general conditions for forest regeneration and for maintaining a long−term demographic stability are unfavorable. Most probably, the regeneration of this type of forest has an episodic, ‘wave−like’ character and corresponds to the ‘catastrophic’ model, according to which the successful regeneration of current dominants (especially Scots pine, silver and downy birch, black alder) must be preceded by a stand−initiating (stand−replacing) disturbance, leading to total or partial, but heavy, destruction of the currently existing stand. At the moment, it would be difficult to predict, however, if and when such a disturbance will affect the stands under investigation. Thus, we predict that in the nearest future at least, the state of overall demographic unbalance will continue or even increase.
    Źródło:
    Sylwan; 2020, 164, 06; 443-453
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Równowaga oksydacyjno-antyoksydacyjna we krwi osób z nagłym niedosłuchem czuciowo-nerwowym po przeprowadzonym pierwszym zabiegu hiperbarii tlenowej – badanie wstępne
    The oxidant–antioxidant equilibrium in the blood of people with sudden sensorineural hearing loss after the first hyperbaric oxygen therapy session—a preliminary study
    Autorzy:
    Paprocki, J.
    Pawłowska, M.
    Sutkowy, P.
    Piechocki, J.
    Woźniak, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1359718.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Medycyny i Techniki Hiperbarycznej
    Tematy:
    nagły niedosłuch czuciowo-nerwowy (SSNHL)
    hiperbaria tlenowa (HBO)
    dysmutaza ponadtlenkowa (SOD)
    katalaza (CAT)
    peroksydaza glutationowa (GPx)
    dialdehyd malonowy (MDA)
    substancje reagujące z kwasem tiobarbiturowym (TBARS)
    sudden sensorineural hearing loss (SSNHL)
    hyperbaric oxygen (HBO)
    superoxide dismutase (SOD)
    catalase (CAT)
    glutathione peroxidase (GPx)
    malondialdehyde (MDA)
    thiobarbituric acid reactive substances (TBARS)
    Opis:
    Oznaczono aktywność wybranych enzymów antyoksydacyjnych: dysmutazy ponadtlenkowej (SOD), katalazy (CAT) i peroksydazy glutationowej (GPx) w erytrocytach oraz stężenie substancji reagujacych z kwasem tiobarbiturowym (TBARS) w osoczu i w erytrocytach osób poddanych działaniu hiperbarii tlenowej (HBO) z powodu wystąpienia nagłego niedosłuchu nerwowo-czuciowego (SSNHL). Krew żylną do badań pobrano bezpośrednio przez zabiegiem HBO oraz ok. 5 min po wyjściu z komory hiperbarycznej. W grupie badanej wyodrębniono 2 podgrupy różniące się wiekiem: grupę I stanowiły osoby poniżej 35 roku życia, grupę II powyżej 50 lat. Uzyskane wyniki poddano analizie statystycznej z wykorzystaniem testu T-Studenta. Za istotne statystycznie uznano różnice przy poziomie istotności p<0,05. Wykazano 5 min po wyjściu z komory hiperbarycznej istotne statystycznie obniżenie się aktywności CAT u wszystkich osób analizowanych łącznie (p<0,01) oraz w I grupie (p<0,05). Zaobserwowano ponadto znamienne statystycznie zmniejszenie się stężenia TBARS w erytrocytach w II grupie chorych (p<0,05). Wykazano, że jednorazowa ekspozycja hiperbaryczna wpływa na równowagę oksydacyjno-antyoksydacyjną o czym świadczy m.in. istotne statystycznie obniżenie się aktywności katalazy w erytrocytach. Możliwe, że odpowiedź antyoksydacyjna na działanie HBO zależy do wieku osób badanych.
    The activity of selected antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) in erythrocytes, and the concentration of thiobarbituric acid reactive substances (TBARS) in blood plasma and erythrocytes, were determined in people subjected to hyperbaric oxygen (HBO) therapy due to sudden sensorineural hearing loss (SSNHL). Venous blood samples were taken immediately before entering the hyperbaric chamber and 5 min after leaving it. In the study group, two age subgroups were distinguished: group I consisting of subjects under 35 and group II consisting of subjects over 50. The obtained values were analysed statistically using Student’s t-test. Differences were considered as statistically significant at p < 0.05. A statistically significant decrease in the CAT activity was shown 5 min after leaving the hyperbaric chamber in pooled subjects (p < 0.01) and group I (p < 0.05). Furthermore, a statistically significant decrease in the erythrocyte TBARS concentration was observed in group II (p < 0.05). It was demonstrated that a single exposure to hyperbaric oxygen affects the oxidant–antioxidant equilibrium as evidenced by, e.g., a statistically significant decrease in the activity of catalase in erythrocytes. It is possible that the antioxidant response to HBO depends on the age of subjects.
    Źródło:
    Polish Hyperbaric Research; 2017, 4(61); 15-24
    1734-7009
    2084-0535
    Pojawia się w:
    Polish Hyperbaric Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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