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Wyszukujesz frazę "heavy" wg kryterium: Temat


Tytuł:
Heavy Subgraph Conditions for Longest Cycles to Be Heavy in Graphs
Autorzy:
Lia, Binlong
Zhang, Shenggui
Powiązania:
https://bibliotekanauki.pl/articles/31340942.pdf
Data publikacji:
2016-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
heavy cycles
heavy subgraphs
Opis:
Let G be a graph on n vertices. A vertex of G with degree at least n/2 is called a heavy vertex, and a cycle of G which contains all the heavy vertices of G is called a heavy cycle. In this note, we characterize graphs which contain no heavy cycles. For a given graph H, we say that G is H-heavy if every induced subgraph of G isomorphic to H contains two nonadjacent vertices with degree sum at least n. We find all the connected graphs S such that a 2-connected graph G being S-heavy implies any longest cycle of G is a heavy cycle.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 2; 383-392
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution of Heavy Metal Fractions in Sewage Sludge from a Selected Municipal Sewage Treatment Plant
Autorzy:
Wojciula, Ada
Boruszko, Dariusz
Kacprzak, Amadeusz
Powiązania:
https://bibliotekanauki.pl/articles/2069929.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
sewage sludge
heavy metals
heavy metal fraction
Opis:
Sewage sludge used for reclamation of egraded areas or in agriculture must have a certain total heavy metal content, as required by law. In practice, however, it is important to carry out a fractional analysis of the elements contained in the sludge. This activity allows to determine the chemical form of a given metal, thanks to which it is possible to assess the assimilability of elements by plants. The study proved that the fraction of certain metals in sewage sludge can vary depending on the period studied. The combination of elements with other compounds in sludge from one treatment plant can vary from month to month. Once analysis has been carried out, it should not be the basis for assessing the bioavailability of metals if sludge from a given treatment plant were to be sampled several times a year.
Źródło:
Rocznik Ochrona Środowiska; 2021, 23; 369--383
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Heavy Metal Fraction Content in Sewage Sludge from Selected Wastewater Treatment Plants
Autorzy:
Wojciula, Ada
Boruszko, Dariusz
Pajewska, Gabriela
Powiązania:
https://bibliotekanauki.pl/articles/1839655.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
sewage sludge
heavy metals
heavy metal fraction
Opis:
Assessment of the assimilability of elements contained in sewage sludge can only be carried out if their fractions, by means of which the chemical form of the element can be identified, are determined. The total content of heavy metals only makes it possible to determine whether the sludge meets the legal requirements and can be used, inter alia, for reclamation, in agriculture or for the adaptation of land to specific needs that result from waste management plans. Therefore, when planning the agricultural use of sewage sludge, attention should be paid above all to the heavy metal fractions contained in it. This is due to the fact that plants do not assimilate every form of element to the same extent. The research and analysis carried out indicate that the metals were most closely related to fractions IV and III, for example they formed connections with silicates, as well as sulphides and organic matter. The metal forms available to plants occupied a small percentage of the total heavy metal content. It was noted that with the metastable fraction of lead increased along with population equivalent. Furthermore, the population equivalent value did not affect the distribution of individual heavy metal fractions in the sludge.
Źródło:
Journal of Ecological Engineering; 2021, 22, 4; 98-105
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Implicit Heavy Subgraphs and Hamiltonicity of 2-Connected Graphs
Autorzy:
Zheng, Wei
Wideł, Wojciech
Wang, Ligong
Powiązania:
https://bibliotekanauki.pl/articles/32083821.pdf
Data publikacji:
2021-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
implicit degree
implicit o-heavy
implicit f-heavy
implicit c-heavy
Hamilton cycle
Opis:
A graph G of order n is implicit claw-heavy if in every induced copy of K1,3 in G there are two non-adjacent vertices with sum of their implicit degrees at least n. We study various implicit degree conditions (including, but not limiting to, Ore- and Fan-type conditions) imposing of which on specific induced subgraphs of a 2-connected implicit claw-heavy graph ensures its Hamiltonicity. In particular, we improve a recent result of [X. Huang, Implicit degree condition for Hamiltonicity of 2-heavy graphs, Discrete Appl. Math. 219 (2017) 126–131] and complete the characterizations of pairs of o-heavy and f-heavy subgraphs for Hamiltonicity of 2-connected graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 1; 167-181
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Content of Heavy Metals and Their Fractions in Organic Soils of Podlasie
Autorzy:
Wiater, Józefa
Powiązania:
https://bibliotekanauki.pl/articles/124491.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
heavy metal
organic soils
speciation of heavy metals
Opis:
The purpose of this study was to determine the total content of cadmium, lead, nickel, copper, zinc and their fractions in organic soils of Podlasie used as permanent grassland. The research material were samples taken from 30 soils of the Podlasie province in 2011-2013. The samples were taken from the determined layer to depth of 0-30 cm. Basic physicochemical properties were determined in the taken soil samples: organic carbon content, pH in 1 M KCl potentiometrically. The total content of metals after mineralization in aqua regia was determined, and cadmium fractions were determined with a modified BCR method. The measurements were conducted by means of atomic absorption spectroscopy with electrothermal atomization using Varian AA-100 spectrometer. It was found that only 2 soils can be included in the soils with first pollution degree due to the cadmium content. The content of other metals was at geochemical background level. The distribution of investigated metals in the fractions in studied organic soils was different comparing to mineral soils. Most of the analyzed elements were present in the fraction associated with organic substance, which limited their mobility, as evidenced by their low share in the available and potentially available fraction. The proportion of metals in the residual fraction was low, which is typical for organic soils. The share of studied metals in particular fractions varied depending on the sampling date, which may be related to the climatic conditions course in the study period and the treatments performed on these soils.
Źródło:
Journal of Ecological Engineering; 2019, 20, 3; 179-184
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy-mineral analysis in Polish investigations of Quaternary deposits: a review
Autorzy:
Marcinkowski, Bogusław
Mycielska-Dowgiałło, Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/94664.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
heavy mineral analysis
heavy mineral resistance
heavy mineral habit
heavy mineral density
Polska
analiza ciężkich minerałów
odporność ciężkich minerałów
gęstość mineralna
Polska
Opis:
The composition of heavy-mineral assemblages is one of the main textural features of sediments because they can have significant value for the interpretation of, among others, their depositional environment, their depositional processes, and their stratigraphic position. Distinctive features of heavy minerals include their resistance to chemical weathering and mechanical abrasion, their habit, and their density. These parameters are the most widely used in the heavy-mineral research of Quaternary deposits in Poland, as well as in such research in other countries conducted by Polish scientists. Several other heavy-mineral parameters can also be used in various types of interpretation. It is discussed whether heavy-mineral analysis is decisive in the evaluation of deposits or whether it plays mainly a role that may support evidence obtained by other types of analysis. The attention is mainly devoted to transparent heavy minerals; the significance of opaque heavy minerals for interpretational purposes is only mentioned.
Źródło:
Geologos; 2013, 19, No. 1-2; 5-23
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy Metals in Soils
Autorzy:
Draszawka-Bołzan, Beata
Powiązania:
https://bibliotekanauki.pl/articles/1153848.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
heavy metals
soils
Opis:
For the purposes of this Issue Paper, metals most commonly found at Superfund sites will be discussed in terms of the processes affecting their behavior in soils, as well as in those of the laboratory methods available to evaluate this behavior. The retention capacity of soil will also be discussed with regard to the movement of metals between the other environmental compartments: ground water, surface water, or the atmosphere. Long-term changes in soil environmental conditions, due to the effects of remediation systems or to natural weathering processes, are also explained with respect to the enhanced mobility of metals in soils.
Źródło:
World News of Natural Sciences; 2015, 2; 20-37
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Leaching of heavy metals from monolithic waste
Autorzy:
Mizerna, K.
Król, A.
Powiązania:
https://bibliotekanauki.pl/articles/208246.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
heavy metals
leaching heavy metals
metale ciężkie
wymywanie metali ciężkich
Opis:
Leaching of heavy metals (Zn, Pb, Cu, Ni and Cr) from hazardous waste originating from steel works (slag) has been investigated. Contaminant leaching behavior from monolithic waste materials in the function of time was examined. There was established the cumulative leaching of elements per surface area of waste material and the impact of the duration of the leachant contact with the waste on the leachability. The types of processes accompanying the release of heavy metals were determined as well. Surface wash-off and dissolution were dominant processes during the leaching of the analyzed elements. Chromium was the only element whose release from the sample was controlled by diffusion when subjected to leaching in a liquid of pH 7. Due to the low levels of heavy metal leaching in relation to their concentrations in the samples, it seems that longer duration of the tank test can contribute to the release of additional amounts of the heavy metals.
Źródło:
Environment Protection Engineering; 2018, 44, 4; 143-158
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beneficiation of oxide ores using dense medium cyclones. A simulation study
Autorzy:
Aghlmandi Harzanagh, A.
Ergun, S. L.
Gulcan, E.
Powiązania:
https://bibliotekanauki.pl/articles/110337.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
heavy medium cyclone
heavy liquid
simulation
iron ores
manganese
chromite
Opis:
Recent investigations of particle behavior and segregation phenomena in a cyclone underline that little is known about particle distribution within a heavy medium separation. For this purpose, density profiles in a heavy medium cyclone (HMC) is measured with techniques such as computational fluid dynamics (CFD) in combination with discrete element modelling (DEM), electrical resistance tomography (ERT), X-ray tomography, particle dynamics analyzer (PDA) etc. Along with these modern efforts of determining the performance of HMC, traditional methods depending on empirical inferences based on experimental data are still important and in progress. The aim of this research was to investigate the possibility of using HMC for the concentration of problematic ores which are not coarsely aggregated. Towards this purpose, current empirical methods were applied to experimental data which were derived from float-sink tests of selected heavy minerals and Fe, Mn, and Cr ore samples. Low density difference between particles made the enrichment difficult using other gravity methods like jigs and shaking tables. After determining physical and mineralogical properties of the samples, appropriate size fractions were prepared for float-sink tests. Combination of sodium polytungstate and tungsten carbide powder were used to prepare non-toxic heavy liquids with density up to 3.5 g/cm3. Using the sink-float test results and existing empirical models for high-density DMC plants simulations were performed. The results of the simulations followed by experimental studies showed that HMCs are applicable to process Fe, Mn, and Cr ores with acceptable grade and recovery.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 379-393
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sewage sludge as barrier material for heavy metals in waste landfill
Autorzy:
Zhang, H.
Yang, B.
Zhang, G.
Zhang, X.
Powiązania:
https://bibliotekanauki.pl/articles/204656.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sewage sludge
hydraulic conductivity
heavy metal pollution
heavy metal retardation
Opis:
Heavy metal pollutants in the leachate of waste landfill are a potential threat to the environment. In this study, the feasibility of using municipal sewage sludge as barrier material for the containment of heavy metal pollutants from solid waste landfills was evaluated by compaction test and hydraulic conductivity test concerning compaction property, impermeability and heavy metal retardation. Results of the compaction test showed that the maximum dry density of 0.79 g·cm−3 was achieved at the optimum water content of about 60%. The hydraulic conductivities of compacted sewage sludge permeated with synthetic heavy metal solutions were in the range of 1.3×10−8 – 6.2×10−9 cm·s−1, less than 1.0 ×10−−7cm·s−1 recommended by regulations for barrier materials. Chemical analyses on the effluent from the hydraulic conductivity tests indicated that the two target heavy metals, Zn and Cd in the permeants were all retarded by compacted sewage sludge, which might be attributed to the precipitation and adsorption of heavy metal ions. The results of this study suggest that specially prepared material from sewage sludge could be used as a barrier for waste landfills for its low permeability and strong retardation to heavy metal pollutants.
Źródło:
Archives of Environmental Protection; 2016, 42, 2; 52-58
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł

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