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Wyszukujesz frazę "buffer capacity" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
The content and composition of organic matter in bottom sediments of the Rybnik reservoir - preliminary studies
Autorzy:
Baran, A.
Mierzwa-Hersztek, M.
Gondek, K.
Szara, M.
Tarnawski, M.
Powiązania:
https://bibliotekanauki.pl/articles/184606.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
bottom sediments
organic matter
buffer capacity
pollutions
Opis:
Organic matter has important influences on the fate of environmental pollution in water dam reservoirs. The aim of the studies was to assess content of organic matter fractions in Rybnik reservoir bottom sediments, and to determine their influence on the content of heavy metals and PAHs. In three sediment samples, the content of C organic (Corg), C extracted (Cex), C humic acid (Cha), C fulvic acid (Cfa) and C non-hydrolyzed (Cnh), buffer capacity, and content of heavy metals and PAHs was analyzed. We found the highest content of Corg, Cex, Cha, Cfa and Cnh in sample 3 (the outlet, near the dam), while the lowest content was found in sample 2 (middle). The fraction of Cnh was dominant in sediment sample 3 (outlet, near dam) and 1 (inlet), whereas the fraction of Cha dominated in sample 2 (middle). Rybnik bottom sediments are characterized by their high buffer capacities (samples 3, 1) shaped among others by the high content of organic matter. The high organic matter content in samples 3 (outlet) and 1 (inlet) and also high total contents of heavy metals and PAHS in these sediments demonstrate that these pollutants have a strong affinity for organic matter in the sediments. Moreover, the highest mobility of metals, from sample 2 (middle), is connected with the low content of organic matter substances and the low buffer capacities of sediments.
Źródło:
Geology, Geophysics and Environment; 2018, 44, 3; 309-317
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potential effect of pH on the leaching of heavy metals from sediments of the Carpathian dam reservoirs
Autorzy:
Szarek-Gwiazda, E.
Powiązania:
https://bibliotekanauki.pl/articles/184689.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Carpathian reservoir
sediments
heavy metals
buffer capacity
pH
Opis:
Eutrophication processes occurring in the Carpathian dam reservoirs (southern Poland) have resulted in a drastic increase of incidences of decrease of pH and oxygen content in near-bottom water, which may affect metal remobilization from the sediment. The study is aimed to determine the buffer capacity and effects of decreasing pH on the remobilization of heavy metals (Cd, Pb, Cu, Zn, Mn and Fe) from sediments of the Dobczycki Reservoir (DR), the Czorsztyński Reservoir (CR), and the Rożnowski Reservoir (RR), the right side tributary of the Vistula River. Buffering capacity and the leaching of heavy metals from sediments accompanied with an increase in acidity were analyzed in 0.00-0.24 M HNO3 solutions. Studied sediments had a high buffer capacity. Buffer capacity of sediments at studied sites of the DR and CR was different due to differences in the composition of sediments. The reservoir sediments had a variable ability to release heavy metals with increasing acidity. At pH ~5 and pH ~3, a considerable leaching of Mn (up to 60% and 85% of the total amount, respectively), Cd (up to 35% and 56% respectively), Pb (up to 25% and 39%), the lower leaching of Cu (up to 18% and 30%) and Zn (up to 14% and 20%), and the lowest leaching of Fe (below 5%) were found. The decrease of pH of the water-sediment system caused by eutrophication processes may affect the mobilization of certain heavy metals (mainly Mn, Cd and Pb) from sediment into the water column of the studied Carpathian reservoirs.
Źródło:
Geology, Geophysics and Environment; 2014, 40, 4; 349-358
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of phosphate ions on buffer capacity of soil humic acids
Autorzy:
Boguta, P.
Sokolowska, Z.
Powiązania:
https://bibliotekanauki.pl/articles/25071.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
phosphate ion
buffer capacity
soil condition
humic acid
wetland
phosphate
plant growth
peat soil
soil parameter
Opis:
The object of this study was to determine change of natural buffer capacity of humic acids by strong buffering agents, which were phosphate ions. Studies were carried out on the humic acids extracted from peat soils. Additional information was obtained by determination of water holding capacity, density, ash and pH for peats and optical parameterQ4/6 for humic acids. Humic acid suspensions exhibited the highest buffer properties at low pH and reached maximum at pH ~ 4. Phosphates possessed buffer properties in the pH range from 4.5 to 8.0. The maximum of buffering was at pH~6.8 and increased proportionally with an increase in the concentration of phosphate ions. The study indicated that the presence of phosphate ions may strongly change natural buffer capacity of humic acids by shifting buffering maximum toward higher pH values. Significant correlations were found for the degree of the secondary transformation with both the buffer capacity and the titrant volume used during titration.
Źródło:
International Agrophysics; 2012, 26, 1
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiline queueing system with random time limitations and limited buffer space
Autorzy:
Tikhonenko, O.
Zając, P.
Powiązania:
https://bibliotekanauki.pl/articles/122703.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
total demands volume
system buffer capacity
loss probability
Stieltjes convolution
system kolejkowy
splot Stieltjesa
pojemność bufora
Opis:
In the paper, we investigate multi-server queueing systems with demands of random space requirements (volumes), in which buffer space is limited by constant value and queueing ore (and) service time are limited by exponentially distributed random variables. For such systems, stationary demands number distribution and loss probability are determined. Some numerical results are attached as well.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2018, 17, 4; 99-106
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Buffer Properties of Forest Soils in Selected Protected Areas
Właściwości buforowe gleb leśnych wybranych obszarów chronionych
Autorzy:
Raczuk, J.
Deska, J.
Powiązania:
https://bibliotekanauki.pl/articles/387992.pdf
Data publikacji:
2012
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
gleby leśne
buforowość gleb
właoeciwości fizyczno-chemiczne gleb
forest soil
buffer capacity
soil physical and chemical properties
Opis:
The paper presents the results of research on forest soil buffer capacity in selected protected areas. The soil buffer capacity was determined for each soil horizon using modified Arrhenius method. Buffer curves were sketched and soil buffer areas were measured with computer techniques. The date obtained were compared with some soil physical and chemical properties using statistical method. Organic (O) and humus (A) horizons of forest soils demonstrate a greater abilities of buffering alkalines than acids whereas buffer capacity of deeper-lying horizons changes as their physical and chemical properties change. Of the examined types of forest soils, the greatest buffer capacity was found for river alluvial soils. The results of the study indicate that the buffer areas are significantly correlated with pH, hydrolytic acidity, content of organic C, clay fractions, sum of exchangeable bases and cation exchangeable capacity.
W pracy przedstawiono wyniki badań nad zdolnościami buforowymi gleb wybranych obszarów chronionych. Analizie poddano 7 profili gleb leśnych reprezentujących następujące podtypy gleb: mady rzeczne brunatne, mady rzeczne próchnicze, gleby płowe zaciekowe, gleby rdzawe brunatne, gleby rdzawe właściwe oraz gleby bielicowe właściwe. Wykreślono dla nich krzywe buforowe zmodyfikowaną metodą Arrheniusa i zmierzono techniką komputerową powierzchnie buforowe gleb. Uzyskane dane porównano statystycznie z niektórymi właściwościami fizyczno-chemicznymi gleb. Poziomy organiczne (O) i próchniczne (A) gleb leśnych wykazują większe zdolności buforowania zasad niż kwasów, natomiast zdolności buforowe poziomów głębiej zalegających zmieniają się wraz z ich właściwościami fizyczno-chemicznymi. Wśród badanych typów gleb leśnych największe zdolności buforowe wykazują mady rzeczne. Wyniki badań wskazują, że powierzchnie buforowe badanych gleb są istotnie skorelowane z pH, kwasowością hydrolityczną, zawartością węgla związków organicznych, frakcja iłu, sumą zasad wymiennych oraz z kationową pojemnością sorpcyjną.
Źródło:
Ecological Chemistry and Engineering. A; 2012, 19, 3; 231-237
1898-6188
2084-4530
Pojawia się w:
Ecological Chemistry and Engineering. A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adenine adsorption in different pH acetate buffer
Autorzy:
Gugała-Fekner, Dorota
Powiązania:
https://bibliotekanauki.pl/articles/2146951.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adenine
adsorption
differential capacity
electroreduction
acetate buffer
Opis:
The research results facilitate the description of adenine adsorption on the mercury electrode with reference to the pH of the supporting electrolyte which was the acetate buffer with pH of 3, 4, 5 and 6. The thermodynamic analysis indicates that the curves of the differential capacity of the studied systems with adenine do not overlap with the curves for the supporting electrolyte – the acetate buffer. This indicates the occurrence of adsorption of the studied compound on the mercury electrode within the whole range of applied concentrations in the case of every tested pH value of the acetate buffer. Adsorption energy and interaction constants were determined using the Frumkin isotherm and the viral isotherm. It was demonstrated that a adenine molecule is adsorbed on the mercury electrode in a buffer with pH 4, 5 and 6 through the negative pole, whereas in a buffer with pH 3 through the positive pole. Physical adsorption was observed in the studied systems. This is indicated by the occurrence of a typical maximum on the curve of the relation the relative surface excess amounts and the potential of the electrode; crossed curves of the following relation surface charge of the electrode from its potential (surface charge of the electrode from its potential σ = f(E)) at one point and, thus, the possibility of determining electrical parameters characterizing maximum adsorption as well as the absence of linearity of the function free energy of adsorption as a function of electrode potential ∆G0 = f(E).
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 2; art. no. 144446
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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