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Tytuł:
On strong automorphisms of direct products of Witt rings. Part 2
Autorzy:
Stępień, M. R.
Stępień, L.
Powiązania:
https://bibliotekanauki.pl/articles/122291.pdf
Data publikacji:
2013
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
Witt rings
strong automorphisms
group rings
Opis:
In the paper strong automorphisms of finitely generated Witt rings are considered. Every finitely generated Witt ring can be expressed in terms of Z / 2Z and basic indecomposable Witt rings using the operations of group ring formation and direct product. Groups of strong automorphisms of basic indecomposables and their direct products and the description of all strong automorphisms of any group Witt ring are known. In this paper the strong automorphisms of direct products of group Witt rings are considered. Presented are two wide classes of Witt rings where the group of strong automorphisms is isomorphic to the direct product of groups of strong automorphisms of Witt rings which are factors in the direct product.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2013, 12, 4; 119-125
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Invo-regular unital rings
Autorzy:
Danchev, Peter V.
Powiązania:
https://bibliotekanauki.pl/articles/747073.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Unit-regular rings
clean rings
strongly clean rings
idempotents
involutions
nilpotents
units
Opis:
It was asked by Nicholson (Comm. Algebra, 1999) whether or not unit-regular rings are themselves strongly clean. Although they are clean as proved by Camillo-Khurana (Comm. Algebra, 2001), recently Nielsen and Ster showed in Trans. Amer. Math. Soc., 2018 that there exists a unit-regular ring which is not strongly clean. However, we define here a proper subclass of rings of the class of unit-regular rings, called invo-regular rings, and establish that they are strongly clean. Interestingly, without any concrete indications a priori, these rings are manifestly even commutative invo-clean as defined by the author in Commun. Korean Math. Soc., 2017.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2018, 72, 1
0365-1029
2083-7402
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some results of reverse derivation on prime and semiprime Γ-rings
Autorzy:
Suliman, Neshtiman
Powiązania:
https://bibliotekanauki.pl/articles/729163.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Prime Γ-rings
semiprime Γ-rings
derivations
reverse derivations
Opis:
In the present paper, it is introduced the definition of a reverse derivation on a Γ-ring M. It is shown that a mapping derivation on a semiprime Γ-ring M is central if and only if it is reverse derivation. Also it is shown that M is commutative if for all a,b ∈ I (I is an ideal of M) satisfying d(a) ∈ Z(M), and d(a ∘ b) = 0.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2015, 35, 1; 53-58
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some mixed matrix problems over several discrete valuation rings
Autorzy:
Gubareni, N.
Powiązania:
https://bibliotekanauki.pl/articles/122874.pdf
Data publikacji:
2013
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
valuation rings
local invariant rings
discrete valuation rings
approximation theorem
mixed flat matrix problems
Opis:
This article presents some results about several district valuation rings with a common skew field of fractions. They are obtained from the approximation theorem for discrete valuation rings. These results give the possibility to solve basic mixed matrix problems for such rings. We present the solution of some mixed flat matrix problems over several district valuation rings with common skew field of fractions.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2013, 12, 4; 47-58
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Localization in semicommutative (m,n)-rings
Autorzy:
Iancu, Lăcrimioara
Pop, Maria
Powiązania:
https://bibliotekanauki.pl/articles/728784.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
(m,n)-rings
semicommutative (m,n)-rings
(m,n)-rings of quotients
(m,n)-division rings
(m,n)-semidomains
n-groups
n-semigroups
Opis:
We give a construction for (m,n)-rings of quotients of a semicommutative (m,n)-ring, which generalizes the ones given by Crombez and Timm and by Paunić for the commutative case. We also study various constructions involving reduced rings and rings of quotients and give some functorial interpretations.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2000, 20, 2; 233-253
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Remarks on Rings
Autorzy:
Obojska, Lidia
O’Hara, Paul
Powiązania:
https://bibliotekanauki.pl/articles/745218.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Distribution law
Rings
Isomorphism
Opis:
Algebraic structures such as Rings, Fields, Boolean Algebras (Set Theory) and \(\sigma\)-Fields are well known and much has been written about them. In this paper we explore some properties of rings related to the distribution law. Specifically, we shall show that for rings there exists only one distribution law. Moreover, for the ring \((Z_{p(p−1)n} +, \cdot)\), where \((p, n) = 1\) there exist isomorphic groups \((G, +)\), \((H, \cdot)\), \(G, H \subset Z_{p(p−1)n}\) of the order \((p − 1)\). Finally, we note that every ring \((Z_{pn}, +, \cdot)\) contains subfields \(\text{mod}(pn)\).
Źródło:
Commentationes Mathematicae; 2010, 50, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiprime FDI-rings
Autorzy:
Gubareni, N.
Powiązania:
https://bibliotekanauki.pl/articles/122728.pdf
Data publikacji:
2014
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
semiprime rings
prime rings
nilpotent ideal
nilpotency index
Jacobson radical
semiperfect ring
complete set of idempotents
FDI-rings
Opis:
In this paper we present some results for FDI-rings, i.e. rings with a complete set of pairwise orthogonal primitive idempotents. We consider the nilpotency index of ideals and give its upper band for ideals in some classes of rings. We also give a new proof of a criterion of semiprime FDI-rings to be prime.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2014, 13, 4; 49-59
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Witt rings of function fields of quasihomogeneous varieties
Autorzy:
Jaworski, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/966718.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Witt rings
graded rings
selfdual vector bundles
quasihomogeneous varieties
residue homomorphisms
Źródło:
Colloquium Mathematicum; 1997, 73, 2; 195-219
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semihereditary rings and related topics
Autorzy:
Gubareni, N.
Powiązania:
https://bibliotekanauki.pl/articles/122027.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Humanistyczno-Przyrodniczy im. Jana Długosza w Częstochowie. Wydawnictwo Uczelniane
Tematy:
semihereditary rings
homological algebra
non commutative rings
pierścienie półdziedziczne
algebra homologiczna
pierścienie nieprzemienne
Opis:
A ring A is called right (left) semihereditary if all finitely generated right (left) ideals of A are projective. In this paper we consider non-commutative semihereditary rings and show their connection with non-commutative valuation rings. We also present some criterion for a module to be flat.
Źródło:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics; 2011, 16; 33-38
2450-9302
Pojawia się w:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A variation of zero-divisor graphs
Autorzy:
Gupta, Raibatak
Sen, M.
Ghosh, Shamik
Powiązania:
https://bibliotekanauki.pl/articles/729141.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rings
zero-divisor graphs
finite fields
Opis:
In this paper, we define a new graph for a ring with unity by extending the definition of the usual 'zero-divisor graph'. For a ring R with unity, Γ₁(R) is defined to be the simple undirected graph having all non-zero elements of R as its vertices and two distinct vertices x,y are adjacent if and only if either xy=0 or yx=0 or x+y is a unit. We consider the conditions of connectedness and show that for a finite commutative ring R with unity, Γ₁(R) is connected if and only if R is not isomorphic to ℤ₃ or $ℤ₂^k$ (for any k ∈ ℕ-{1}\). Then we characterize the rings R for which Γ₁(R) realizes some well-known classes of graphs, viz., complete graphs, star graphs, paths (i.e., $P_n$), or cycles (i.e., $C_n$). We then look at different graph-theoretical properties of the graph Γ₁(F), where F is a finite field. We also find all possible Γ₁(R) graphs with at most 6 vertices.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2015, 35, 2; 159-176
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Automatic search of automorphisms of Witt rings
Autorzy:
Stępień, L.
Stępień, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/121845.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Humanistyczno-Przyrodniczy im. Jana Długosza w Częstochowie. Wydawnictwo Uczelniane
Tematy:
Witt rings
automorphisms
strong automorphisms
automorphisms of Witt rings
pierścień Witta
automorfizm
automorfizmy pierścieni Witta
Opis:
The investigation of strong automorphisms of Witt rings is a difficult task because of variety of their structures. Cordes Theorem, known in literature as Harrison-Cordes criterion (cf. [1, Proposition 2.2], [3, Harrison's Criterion]), makes the task of describing all the strong automorphisms of a given (abstract) Witt ring W = (G, R) easier. By this theorem, it suffices to find all such automorphisms ơ of the group G that map the distiguished element -1 of the group G into itself (i.e. ơ(-1) = -1) in which the value sets of 1-fold Pfister forms are preserved in the following sense: ơ(D(1, α)) = D(1, ơ(α)) for all α ∈ G. We use the above criterion and the well-known structure of the group G as a vector space over two-element field F2 for searching all automorphisms of this group. Then we check Harrison-Cordes criterion for found automorpisms and obtain all the automorpisms of a Witt ring W. The task is easy for small rings (with small groups G). For searching of all strong automorpisms of bigger Witt rings we use a computer which automatizes the procedure described above. We present the algorithm for finding strong automorphisms of a Witt rings with finite group G and show how this algorithm can be optimized.
Źródło:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics; 2011, 16; 141-146
2450-9302
Pojawia się w:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lie ideals in prime Γ-rings with derivations
Autorzy:
Suliman, Nishteman
Majeed, Abdul-Rahman
Powiązania:
https://bibliotekanauki.pl/articles/728934.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
prime Γ-rings
Lie ideals
derivations
Opis:
Let M be a 2 and 3-torsion free prime Γ-ring, d a nonzero derivation on M and U a nonzero Lie ideal of M. In this paper it is proved that U is a central Lie ideal of M if d satisfies one of the following
(i) d(U)⊂ Z,
(ii) d(U)⊂ U and d²(U)=0,
(iii) d(U)⊂ U, d²(U)⊂ Z.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2013, 33, 1; 49-56
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On strong automorphisms of direct products of Witt rings. Part 1
Autorzy:
Stępień, M. R.
Stępień, L.
Powiązania:
https://bibliotekanauki.pl/articles/973617.pdf
Data publikacji:
2013
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
Witt rings
quaternionic structures
strong automorphisms
Opis:
The notion of Witt ring is fundamental in bilinear algebra. Automorphisms of Witt rings have been investigated until recent years. In this paper we consider Witt rings which are direct products of finite number of other Witt rings. We shall present a necessary condition in order to group of all strong automorphisms of direct product of Witt rings be a direct product of groups of strong automorphisms of Witt rings which are factors in the direct product. Subsequently, there are considered some examples of Witt rings, where described condition is fulfilled.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2013, 12, 3; 123-133
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some homological properties of skew PBW extensions arising in non-commutative algebraic geometry
Autorzy:
Lezama, Oswaldo
Powiązania:
https://bibliotekanauki.pl/articles/38117319.pdf
Data publikacji:
2017-06-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Auslander regularity condition
Cohen-Macaulay rings
strongly noetherian algebras
skew PBW extensions
filtered-graded rings
point modules
Opis:
In this short paper we study for the skew PBW (Poincar-Birkhoff-Witt) extensions some homological properties arising in non-commutative algebraic geometry, namely, Auslander-Gorenstein regularity, Cohen-Macaulayness and strongly noetherianity. Skew PBW extensions include a considerable number of non-commutative rings of polynomial type such that classical PBW extensions, quantum polynomial rings, multiplicative analogue of the Weyl algebra, some Sklyanin algebras, operator algebras, diffusion algebras, quadratic algebras in 3 variables, among many others. Parametrization of the point modules of some examples is also presented.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2017, 37, 1; 45-57
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fossil wood from the Roztocze region (Miocene, SE Poland) : a tool for palaeoenvironmental reconstruction
Autorzy:
Kłusek, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059126.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Roztocze
fossil wood
wood anatomy
growth rings
Opis:
This article presents the results of anatomical and growth ring analyses of Badenian fossil wood from the Roztocze region. All the wood specimens examined are classified as Taxodioxylon taxodii Goth. The growth rings of these woods are very narrow, and they vary considerably in width. Tracheids have large diameters and thin cell walls.The latewood zone is wide; the transition between early and latewood is gradual. Both false and wedge rings and also reaction wood zones are often found. These characteristics of the fossil wood make it a suitable aid to reconstructing the environmental conditions prevailing while the trees were alive. The environmental requirements of these ancient Roztocze trees are interpreted by comparison with those of their nearest living relatives, with the conclusion that they lived in waterlogged or temporarily flooded stands under seasonally changing environmental conditions and with a long growing season. The climate was warm and humid and characterized by significant variability, mainly as regards the amount of precipitation.
Źródło:
Geological Quarterly; 2006, 50, 4; 465-474
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Automatic search of rational self-equivalences
Autorzy:
Stępień, L.
Stępień, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/950276.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Humanistyczno-Przyrodniczy im. Jana Długosza w Częstochowie. Wydawnictwo Uczelniane
Tematy:
rational self-equivalences
automorphisms of Witt rings
Witt rings
algebra
algorithm
automatic search
automorfizm
pierścień Witta
algorytm
Opis:
Two Witt rings that are not strongly isomorphic (i.e., two Witt rings over two fields that are not Witt equivalent) have different groups of strong automorphisms. Therefore, the description of a group of strong automorphisms is different for almost every Witt ring, which requires the use various tools in proofs. It is natural idea to use computers to generate strong automorphisms of the Witt rings, which is especially effective in the case of the finitely generated Witt rings, where a complete list of strong automorphisms can be created. In this paper we present the algorithm that was used to generate strong automorphisms from the infinite group of strong automorphisms of the Witt ring of rational numbers W(Q).
Źródło:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics; 2018, 23; 67-74
2450-9302
Pojawia się w:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of maximum crankcase pressure for evaluation of the piston-rings- cylinder assembly
Autorzy:
Abramek, K.F.
Abramek, F.
Powiązania:
https://bibliotekanauki.pl/articles/242436.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
blow-by
wear
piston
rings
cylinder
crankcase
Opis:
In the paper is presented statistical analysis of the effect of compression-ignition engine working time on the phenomenon of exhaust gas maximum pressure increase in crankcase and cylinder liner, pistons and rings wear. Characteristics of the crankcase maximum pressure variations were made for the start-up speed and for selected rotational speeds of the 359 compression-ignition engine crankshaft as well as micrometric measurements of the cylinder liner and pistons and rings wear. The engine was operated under normal traction conditions while pressure analyses and cylinder liner micrometric measurements were made, respectively, after an operational run of 204864 km. Crankcase exhaust gas maximum pressure measurements were made both with air vent open and closed for a cold (lubricating oil temperature of 285 K) and a warm engine (333 K). Basing on the analysis of obtained examination results, it was showed that crankcase exhaust gas maximum pressure measurement (also during the start-up) may be used for determination of engine run and life. Average and maximum wear and tear of cylinder liner s, maximum wear and tear of pistons in the perpendicular plane to the piston pin axis, dependency of maximum crankcase pressure in the function of operational mileage of a 359 engine for lubricating oil temperature of 333 K, dependency of maximum crankcase pressure in the function of operational mileage for lubricating oil temperature of 285 K are presented.
Źródło:
Journal of KONES; 2009, 16, 2; 23-28
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Climatic sensitivity of delta13C in tree rings of Quercus robur L., Populus tremula L. and Pinus sylvestris L. in Vilnius region (eastern Lithuania)
Autorzy:
Barisevičiūtė, Rūta
Skipitytė, Raminta
Pukienė, Rutilė
Lapeikaitė, Indrė
Kakaras, Irmantas
Remeikis, Vidmantas
Powiązania:
https://bibliotekanauki.pl/articles/956802.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
δ13c
climate
tree-rings
dendroclimatology
Opis:
The aim of this work was to evaluate the possibilities of using carbon isotope measurements to determine a strong climate signal of trees influenced by the pollutant stress as well as to examine the difference in reaction of several investigated species to the climate change. Eurasian aspen (Populus tremula), pedunculate oak (Quercus robur) and Scots pine (Pinus sylvestris) trees from Vilnius region were selected for the stable carbon isotope analysis. Our results showed that over the last 70 years (1940–2009) the climate during summer months was the most important factor for the variation of stable carbon isotope values in tree rings, but its influence on different tree species slightly differed. δ13C measurements in Eurasian aspen best corresponded to the air temperature and the precipitation signal in July–August. Oak was more sensitive to the temperature and relative humidity in June–July. A positive correlation coefficient with temperature in the period of transition from the previous vegetation to dormancy season (previous September–October) was specific to oak as well. Scots pine grown at a polluted site was sensitive only to precipitation in summer months of the growing season. The correlation between δ13C measurements and climate data was determined to be from low to moderate in all the investigated trees and did not exceed the value of |r| ≥ 0.71 suggested by McCarroll et al. (2003) as a necessary value for the reliable climate reconstruction. However, the highest correlation coefficient values of 0.65 and 0.61, obtained between the maximal air temperature throughout the hydrological year (previous September–current August) and δ13C in oak rings or between mean monthly sunshine hours throughout July–August and δ13C values in aspen rings, respectively, are comparable with those used in many palaeoclimatic reconstructions that were based even on weaker correlations.
Źródło:
Dendrobiology; 2017, 78; 1-9
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zmienność wybranych cech makrostruktury i gęstości drewna dębu czerwonego (Quercus rubra L.) z Polski południowo-wschodniej
Variability of selected macrostructural features and the wood density of northern red oak (Quercus rubra L.) from south-eastern Poland
Autorzy:
Wąsik, R.
Michalec, K.
Powiązania:
https://bibliotekanauki.pl/articles/979284.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
red oak
sapwood
annual rings
latewood
density
Opis:
The aim of the paper was to determine the variability of selected macrostructural features and wood density for northern red oak growing in south−eastern Poland. On 4 study plots, we sampled each tree, taking an increment core from the northern side of the trunk, from the height of 1.3 m. The number of tree rings, width and the share of sapwood was measured. The cores were scanned and then tree ring and latewood widths were measured. The latewood proportion in each ring was calculated. Next, starting from the bark, the cores were divided into sections containing 10 annual rings. The relative wood density was determined for each section, then the density was calculated for entire stem cross−section. The mean sapwood width was 1.5 cm. It included 7 annual rings on average, and its share in the trunk cross−sectional area reached 17%. Younger red oaks (II and III age classes) had a significantly higher share of sapwood compared to older trees (IV and V age classes). The investigated red oaks formed narrow−ring wood with an average width of 2.16 mm. The trees growing on deciduous forest habitat had a more equal tree ring width compared to trees from coniferous forest habitats, where this feature showed also higher variability. The latewood proportion in the studied red oaks was 60% on average. The mean relative wood density was 0.578 g/cm3 and it was slightly higher than the value given for red oaks growing in North America. The calculated absolute density (with an assumed volumetric shrinkage from 12.9 to 13.7%) varied from 0.664 to 0.670 g/cm3. It classifies the investigated wood as moderately heavy. Similar density values are given for native oaks, which allows to assume that the technical quality of the wood of red oaks growing in Poland is similar to native oak species. The wood of trees from deciduous forest habitat showed a significantly higher density and a more equal distribution compared to the trees from coniferous forest sites. The raw material of red oaks obtained from deciduous forest habitats should characterize by a better technical quality of wood in comparison with that obtained from coniferous forest sites.
Źródło:
Sylwan; 2020, 164, 10; 850-859
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mutational witches’ broom impact on the growth of the parent branch in several Pinaceae species
Autorzy:
Zhuk, E.
Vasilyeva, G.
Goroshkevich, S.
Powiązania:
https://bibliotekanauki.pl/articles/2077653.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
somatic mutation
annual rings
crown part interaction
Opis:
Mutational witches’ broom is a part of the tree crown with abnormally dense branching and slow shoot growth, which putatively originates from a cell in a bud apical meristem and can be visually differentiated from the normal crown. The witches’ broom forms a large branching system which competes sufficiently with other parts of the tree crown. However, the competitive relationship and the interaction between the mutant and normal crown parts have not yet been studied. We investigated the patterns and dynamics of the competitive relationship between witches’ broom and normal branching systems of the same tree of five Pinaceae species by tree ring analysis. Three saw-cuts were made in each tree: on the lateral branch with the witches’ broom, on the proximal part of the axial branch in front of the branch with the witches’ broom, on the distal part of the axial branch right after the branch with the witches’ broom. An- nual radial growth was measured to the nearest 0.01 mm, and annual ring areas from three saw-cuts were analysed to compare the growth dynamics before and after witches’ broom appearance. The growth of the lateral branch with the witches’ broom sharply increased in the year of witches’ broom appearance by 2–10 times. The growth of the distal part of the axial branch sharply decreased in the same year, which could be explained only by the witches’ broom appearance. All branches with witches’ brooms gradually became thicker than the distal part of the branch, 3–150 times at the peak of growth, and occasionally outgrew even the proximal part of the branch. Thus, witches’ broom is drastically morphologically and physiologically different from the rest of the crown. All witches’ brooms had their own vertically oriented axis of symmetry and represented autonomous branching systems that were not subordinate to any other branching systems. They break the normal donor-acceptor relationship in a tree and eagerly consume resources without being fully involved in their production. The mutation clearly affects the hormonal regulation of growth and morphogenesis and turns a witches’ broom into a new metabolic sink.
Źródło:
Dendrobiology; 2020, 83; 52-59
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problemy profilowania i eksploatacji powierzchni roboczej elementów formujących pras walcowych
Some problems of surface shaping and the exploitation of the forming elements of roller presses
Autorzy:
Janewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/258414.pdf
Data publikacji:
2010
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Eksploatacji - Państwowy Instytut Badawczy
Tematy:
elementy formujące
wgłębienia formujące
brykieciarka walcowa
konstrukcja
eksploatacja
roller press
forming rolls
forming rings
pocket shapes
rings design
exploitation
Opis:
W artykule przedstawiono niektóre czynniki mające wpływ na profilowanie walcowej powierzchni roboczej narzędzi formujących brykieciarek walcowych. Narzędzia te stanowią zasadniczy element określający możliwości stosowania i eksploatacji tych urządzeń. Właściwy wybór rodzaju i kształtu wgłębień formujących oraz sposobu ich rozmieszczenia, czyli ukształtowanie powierzchni roboczej ma istotny wpływ na proces zagęszczania i scalania materiałów drobnoziarnistych. Wybór tworzywa konstrukcyjnego oraz odpowiednich metod jego obróbki, a także technika wykonywania wgłębień formujących decydują o eksploatacji i trwałości narzędzi i prasy oraz o prawidłowym przebiegu procesu brykietowania. Przedstawiono również podstawy geometrycznego kształtowania wgłębień formujących i ich rozmieszczenia na walcowej powierzchni elementu formującego, tzn. pierścienia, walca lub segmentu. Rozważono przypadek podstawowy, tzn. brykiet w kształcie "poduszki" z płaszczyzną podziału.
Some of the factors affecting the shaping of the cylindrical working surface of tools (i.e. rings) used in roller-presses for briquetting are presented. These tools are an essential element in determining the applicability and operation of these devices. They often suffer heavy abrasive wear, and they are highly mechanically loaded. The appropriate choice of the type and shape of the mould cavities (pockets) and how they are deployed, that is the shaping the working surface, has a significant influence on the process of compaction and consolidation of fine-grained materials. Choosing material for forming rolls (rings, segments, or cylinder) and corresponding methods of treatment and exercise technique cavities forming operation determine the tool life and the press and smooth the process of briquetting. The article also presented a simplified method of shaping and placement of pockets on the cylindrical surface of the ring, cylinder, or a segment. Considered is the basic case, i.e. briquette plane of division.
Źródło:
Problemy Eksploatacji; 2010, 2; 149-157
1232-9312
Pojawia się w:
Problemy Eksploatacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical model of piston ring sealing in combustion engine
Autorzy:
Koszałka, G.
Guzik, M
Powiązania:
https://bibliotekanauki.pl/articles/258834.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
exhaust gas blow-by
displacements of rings
twisting of rings
oil film
cylinder
piston
ring
mathematical model
lubrication
Opis:
This paper presents a mathematical model of piston-rings-cylinder sealing (TPC) of a combustion engine. The developed model is an itegrated model of gas flow through gaps in TPC unit , displacements and twisting motions of piston rings in ring grooves as well as generation of oil film between ring face surfaces and cylinder liner. Thermal deformations and wear of TPC unit elements as well as heat exchange between flowing gas and surrounding walls , were taken into account in the model. The paper contains descriptions of: assumptions used for developing the model , the model itself, its numerical solution as well as its computer application for carrying out simulation tests.
Źródło:
Polish Maritime Research; 2014, 4; 66-78
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noethérianité de certaines algèbres de fonctions analytiques et applications
Autorzy:
Elkhadiri, Abdelhafed
Hlal, Mouttaki
Powiązania:
https://bibliotekanauki.pl/articles/1207892.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Nash functions
regular rings
analytic algebra
subanalytic sets
Opis:
Let $M ⊂ ℝ^{n}$ be a real-analytic submanifold and H(M) the algebra of real analytic functions on M. If K ⊂ M is a compact subset we consider $S_{K}={f ∈ H(M)| f(x) ≠ 0 \ \text{for all} \ x ∈ K}$; $S_{K}$ is a multiplicative subset of $H(M)$. Let $S_{K}^{-1}H(M)$ be the localization of H(M) with respect to $S_{K}$. In this paper we prove, first, that $S_{K}^{-1}H(M)$ is a regular ring (hence noetherian) and use this result in two situations:
   1) For each open subset $Ω ⊂ ℝ^{n}$, we denote by O(Ω) the subalgebra of H(Ω) defined as follows: f ∈ O(Ω) if and only if for all x ∈ Ω, the germ of f at x, $f_{x}$, is algebraic on $H(ℝ^{n})$. We prove that if Ω is a bounded subanalytic subset, then O(Ω) is a regular ring (hence noetherian).
   2) Let $M ⊂ ℝ^{n}$ be a Nash submanifold and N(M) the ring of Nash functions on M; we have an injection N(M) → H(M). In [2] it was proved that every prime ideal p of N(M) generates a prime ideal of analytic functions pH(M) if M or V(p) is compact. We use our Theorem 1 to give another proof in the situation where V(p) is compact. Finally we show that this result holds in some particular situation where M and V(p) are not assumed to be compact.
Źródło:
Annales Polonici Mathematici; 2000, 75, 3; 247-256
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nowe biodegradowalne pierścienie do zespalania jelita grubego
New biodegradable rings for large intestine integration
Autorzy:
Drop, R.
Mazurkiewicz, S.
Szaraniec, B.
Woźny, Z.
Gryń, K.
Cygan, R.
Powiązania:
https://bibliotekanauki.pl/articles/285186.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
implanty
biomateriały
pierścienie zespalające
implants
biomaterials
biodegradable rings
Opis:
Próby łączenia jelit za pomocą implantów sięgają początków XIX w, kiedy to opracowane zostały pierwsze pierścienie zespalające przez Denansa (1827) i Henroza (1826). Kolejna konstrukcja zaproponowana przez Murphyego, tzw. guzik Murphyego, stała się inspiracją dla komercyjnych implantów, ulegających fragmentacji pierścieni Valtrac® (Biofragmentable Anastomotic Ring) do zespoleń jelitowych, których produkcję w latach osiemdziesiątych XX wieku rozpoczęła firma Davis & Geck. Równocześnie rozwijane były techniki zespalania jelit za pomocą staplerów (Hültl 1908, Petz 1924, Androsov 1950), które również w latach osiemdziesiątych XX wieku stały się jednym ze standardów postępowania w chirurgii jelita grubego. Prace nad opracowaniem skutecznego, łatwego w aplikacji i ulegającego w pełni biodegradacji implantu do zespoleń jelit nadal trwają. Zakładają one dążenie do możliwie najmniejszego uszkodzenia tkanek, zapewnienia szczelności zespolenia i odpowiedniej wielkości jego światła, przy zachowaniu prawidłowego ukrwienia i niewywoływaniu nadmiernego napięcia w jelitach. Jedną z propozycji nowoczesnego rozwiązania problemu związanego z zespalaniem jelita grubego może stanowić w pełni biodegradowalny układ pierścieni wykonany z poliestrów alifatycznych mocowanych bezszwowo. Aplikacja pierścieni zakłada odwinięcie zespalanych części jelita na zewnątrz jego światła, a następnie ich połączenie przez docisk dzięki odpowiedniemu systemowi blokującemu. Prototypy implantów do zespalania jelit otrzymano metodą wtrysku przy użyciu wtryskarki ślimakowej Multiplas. Temperatura wtrysku wynosiła 160-170°C, a ciśnienie w układzie 60-90 kg/cm2. Prototypy implantów wykonano z polimeru resorbowalnego - polilaktydu PLA firmy NatureWork, USA (PLA Ingeo 3251D). Pierwsze doświadczenia prowadzone in vitro i in vivo wskazują, że wykonane implanty mogą z powodzeniem spełniać wspomniane powyżej założenia i dodatkowo dzięki łatwej aplikacji znacznie skrócić czas trwania operacji. Zaproponowana konstrukcja układu pierścieni oraz właściwości fizyko-mechaniczne zastosowanego materiału polimerowego pozwoliły w prosty sposób zespolić jelito uzyskując jednakowy regulowany docisk na jego obwodzie.
The attempts at integrating intestines by means of implants date back to the beginning of the 19th century, when integrating rings were developed by Denans (1827) and Henroz (1826). Another construction, proposed by Murphy, the, so called, Murphy’s button, became an inspiration for commercial implants – the Valtrac® fragmentable rings (Biofragmentable Anastomotic Rings) for intestine integration, whose production was initiated in 1980s by Davis & Geck. Simultaneously developed were techniques of intestine integration with the use of staplers (Hültl 1908, Petz 1924, Androsov 1950), which, also in the 1980s, became one of the standards for large intestine surgery procedures. Works on the development of an effective, easily applicable and fully biodegradable implant for intestine integration are still being conducted. The main goal, providing a minimal tissue damages, is to obtain a leakproof anastomosis with a proper size of its inner diameter along with the preservation of the adequate blood supply and no excessive tensions in the intestines. One of the proposals of a modern solution to the problem connected with large intestine integration can be a fully biodegradable system of rings made of seamless-mounted aliphatic polyesters. The applying procedure assumes turning parts of the intestine, which are meant to be integrated, inside-out and stretching their edges on the rings. Next, rings are joined together by pressing them “face to face” and locking with the appropriate seamless blocking system. Prototypes of large intestine integration implants were obtained by the injection moulding (screw injection moulding machine Multiplas). The injection temperature was 160-170°C and the pressure in the system was 60-90 kg/cm2. The implant prototypes were prepared from a polymer – the PLA polylactide by NatureWork, USA (PLA Ingeo 3251D). The initial in vitro and in vivo experiments show that the elaborated implants can successfully meet the above mentioned assumptions and, additionally, because of their easy application, significantly shorten the time of the surgical procedure. The proposed construction of the ring system and the physico-mechanical properties of the applied polymer material made it possible to easily integrate the intestine and achieve a similar, regulated, pressure on its circumference.
Źródło:
Engineering of Biomaterials; 2013, 16, no. 122-123 spec. iss.; 56-57
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wave propagation in piezoelectric rings with rectangular cross-sections
Autorzy:
Zhang, X.
Wang, Y.
Chen, H.
Powiązania:
https://bibliotekanauki.pl/articles/279995.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
piezoelectric rings
orthogonal polynomial
guided wave
dispersion curves
Opis:
The ring ultrasonic transducers are widely used in the ocean engineering and medical fields. This paper employs an extended orthogonal polynomial approach to solve the guided wave propagation in two-dimensional structures, i.e. piezoelectric rings with rectangular cross- -sections. The extended polynomial approach can overcome the drawbacks of the conven- tional orthogonal polynomial approach which can be used to solve wave propagation in one-dimensional structures. Through numerical comparison with the available results for a rectangular aluminum bar, the validity of the present approach is illustrated. The dispersion curves and displacement and electric potential distributions of various rectangular piezo- electric rings are calculated, and the effects of different radius to thickness ratios, width to height ratios and polarizing directions on the dispersion curves are illustrated.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 673-682
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on additive groups of some specific torsion-free rings of rank three and mixed associative rings
Autorzy:
Najafizadeh, Alireza
Woronowicz, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/38148434.pdf
Data publikacji:
2017-12-20
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rank
type
square subgroup
additive groups of rings
Opis:
It is studied how rank two pure subgroups of a torsion-free Abelian group of rank three influences its structure and type set. In particular, the criterion for such a subgroup B to be a direct summand of a torsion-free Abelian group of rank three with the finite type set containing the greatest element which does not belong to the type set of B, is presented. Some results for nil groups and the square subgroup of a decomposable torsion-free Abelian group are also achieved. Moreover, new results for mixed Abelian groups supporting only associative rings are obtained. In particular, the first example of an Abelian group supporting only associative rings but not only commutative rings is given.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2017, 37, 2; 223-232
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the shape of n-derivations
Autorzy:
Maciejewski, Maciej
Prószyński, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/962659.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
n-derivations
ideals of commutative rings
higher degree mappings
Opis:
We present some classification results for n-derivations over certain commutative rings.
Źródło:
Commentationes Mathematicae; 2019, 59, 1-2; 19-32
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lubricating oil consumption at low temperatures
Autorzy:
Iskra, A.
Krzymień, A.
Krzymień, P.
Powiązania:
https://bibliotekanauki.pl/articles/245728.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
piston rings
oil film
lubricating oil consumption
friction losses
Opis:
The problem of lubricating oil consumption still seems to be important one at least because of the use of DPFs in exhaust systems of diesels. Even a minor consumption can be a source of particulate matter that blocksfilters. On the other hand formation of oil film parameters that guarantee minimum oil consumption could lead to the increased friction losses. Ali these remarks relate to the nominal temperature ofoperation. Situation can differ at temperature of cold start. Presented paper deals the problem of oil consumption at lower temperatures. The observation concerning friction losses under these conditions are mentioned as well. Parameters influencing the lubricating oil consumption, oil consumption at nominal temperature of engine run, oil consumption at low temperature are presented in the paper. As well course of oil film thickness, layer thickness and friction force for upper compression ring at engine nominal temperature of operation, course of oil film thickness, layer thickness and friction force for upper compression ring at lower engine run temperature, ring face wetting level at nominal temperature of operation, ring face wetting level at lower temperature of operation, lubricating oil consumption and friction losses generated by ring pack of single cylinder are subject of the paper.
Źródło:
Journal of KONES; 2009, 16, 4; 163-170
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A first Catalgorithm?
Autorzy:
Geneste, J.-F.
Powiązania:
https://bibliotekanauki.pl/articles/226651.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
non commutative rings
zero-knowledge proofs
finite type module
Opis:
We propose building a new PKC in a ring structure, the classification of rings being an open problem. The difficulty of the scheme is based on retrieving the eigenvalues of endomorphism on a finite type module over a non-commutative ring. It is resistant to a chosen cipher text attack. Working in the fraction ring of a non-commutative ring makes our scheme a zero-knowledge proof of knowledge, result indistinguishable, in the Naor-Yung model. Finally, a dramatic improvement in security is obtained through the drawing with uniform probability of the working ring at high frequency.
Źródło:
International Journal of Electronics and Telecommunications; 2018, 64, 2; 185-188
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon-13 in alpha-cellulose of oak latewood (Jędrzejów, Southern Poland) during the Maunder Minimum
Autorzy:
Pazdur, A.
Korput, S.
Fogtman, M.
Szczepanek, M.
Hałas, S.
Krąpiec, M.
Szychowska-Krąpiec, E.
Powiązania:
https://bibliotekanauki.pl/articles/2058897.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
13C isotope
alpha-cellulose
Maunder Minimum
tree-rings
Opis:
We have studied the δ13C signature in latewood alpha-cellulose of an ancient oak (Quercus robur L.) from a Cisterian Abbey belfry in Jędrzejów (Southern Poland). The time scale for the delta 13C record during 1631-1765 AD was built on the basis of detailed dendrochronology studies. Techniques available for extraction of alpha-cellulose from small samples have been used, the mean value of alpha-cellulose extraction efficiency being ca. 35%. In the delta 13C record of alpha-cellulose the cooling between 1650-1700 AD is clearly visible as a decrease of about 1.5‰. This period is consistent with the interval of the lowest solaractivity between 1645 and 1715 AD, which is known as the Maunder Minimum. Anti-correlation between δ13C and δ13C during the Maunder Minimum was observed but δ13C record is delayed by about 30 years with respect to the Maunder Minimum.
Źródło:
Geological Quarterly; 2005, 49, 2; 165-172
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Growth drivers of monumental wild service tree (Sorbus torminalis) out of its natural range in Kyiv, Ukraine
Autorzy:
Prokopuk, Y.
Leshcheniuk, O.
Sukhomlyn, M.
Matiashuk, R.
Budzhak, V.
Netsvetov, M.
Powiązania:
https://bibliotekanauki.pl/articles/2130184.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
wild service tree
tree-rings
growth pattern
climatic factors
Opis:
Wild service tree (Sorbus torminalis) is a rare, endangered, relict species, that is protected by law in many European countries. Outside the species distribution range, the trees are usually planted in botanical gardens, parks, arboretums, and at the roadside. Such old introduced trees are an important source of knowledge about species’ acclimation process and current growth-limiting factors in the new environment. In Kyiv, the oldest live S. torminalis trees have been planted in botanical gardens and arboretums after the 1950s. In addition, some trees of this species are preserved in front of the historical building Liberman’s mansion, but the year of their planting remains unknown. Regarding dendroclimatological investigations of this species are scarce and have been provided only in Central European forests, a detailed analysis of the species growth-to-climate relationships should be performed not only the species’ natural range but also in its secondary ranges. In this article, we studied three S. torminalis trees in a historical place in Kyiv to determine their age and evaluate environmental conditions driving the growth of this rare species out of its natural range in Kyiv. To reach our goal we used the dendrochronological approaches, i.e. tree-ring dating, partial correlation analysis using stationary and moving time windows. Our results showed that S. torminalis trees were planted after the last building owner S. Liberman’s death (1917). The studied trees are the oldest of known alive S. torminalis trees in Kyiv. Dendroclimatological results revealed S. torminalis is sensitive to higher air temperature and moisture excess in the period of wood formation in Kyiv. S. torminalis trees at 2 Bankova Street are the oldest species examples in Kyiv and have important historical, cultural, and scientific values. S. torminalis species could be widely used in urban forestry, particularly in regions with projected soil moisture shortening.
Źródło:
Dendrobiology; 2022, 87; 163-170
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correspondences between ideals and \(z\)-filters for rings of continuous functions between \(C^∗\) and \(C\)
Autorzy:
Panman, Phyllis
Sack, Joshua
Watson, Saleem
Powiązania:
https://bibliotekanauki.pl/articles/745481.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Rings of continuous functions
Ideals
\(z\)-filters
Kernel
Hull
Opis:
Let \(X\) be a completely regular topological space. Let \(A(X)\) be a ring of continuous functions between \(C^∗(X)\) and \(C(X)\), that is, \(C^∗(X) \subset A(X) \subset C(X)\). In [9], a correspondence \(\mathcal{Z}_A\) between ideals of \(A(X)\) and \(z\)-filters on \(X\) is defined. Here we show that \(\mathcal{Z}_A\) extends the well-known correspondence for \(C^∗(X)\) to all rings \(A(X)\). We define a new correspondence \(\mathcal{Z}_A\) and show that it extends the well-known correspondence for \(C(X)\) to all rings \(A(X)\). We give a formula that relates the two correspondences. We use properties of \(\mathcal{Z}_A\) and \(\mathcal{Z}_A\) to characterize \(C^∗(X)\) and \(C(X)\) among all rings \(A(X)\). We show that \(\mathcal{Z}_A\) defines a one-one correspondence between maximal ideals in \(A(X)\) and the \(z\)-ultrafilters in \(X\).
Źródło:
Commentationes Mathematicae; 2012, 52, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie pierścieni Białeckiego jako turbulizatorów zwiększających sprawność wymiennika ciepła
Application of Białecki rings as turbuli- zers augmenting heat transfer efficiency of a heat exchanger
Autorzy:
Dziak, J.
Ratajczak, K.
Powiązania:
https://bibliotekanauki.pl/articles/2072056.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
pierścienie Białeckiego
turbulizatory
wymiana ciepła
Bialecki rings
turbulizer
heat transfer
Opis:
W pracy przedstawiono wyniki badań ruchu ciepła w wymienniku typu rura w rurze, wypełnionym pierścieniami Białeckiego, jako turbulizatorami cieczy. Zastosowanie turbulizatorów powoduje 1,5+2-krotny wzrost wartości współczynników przenikania ciepła w stosunku do rury pustej. Zastosowanie turbulizatorów w postaci pierścieni Białeckiego powoduje ok. 100-krotny wzrost spadku ciśnienia cieczy przepływającej w rurze w stosunku do rury bez wypełnienia.
Results of heat transfer research carried out in a double-pipe heat exchanger filled with Bialecki rings are presented in the paper. Application of turbuli- zers caused the increase of overall heat transfer coefficients by 1.5+2 times in comparison with a heat exchanger without rings. Usage of Bialecki rings led to about 100 times growth of pressure drop of liquid flowing in the heat exchanger in comparison with a heat exchanger without rings. Keywords: Bialecki rings, turbulizer, heat transfer.
Źródło:
Inżynieria i Aparatura Chemiczna; 2014, 1; 17--18
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda azotowania ZeroFlow jako sposób redukcji zużycia pierścieni tłokowych
Reducing wear of piston rings using ZeroFlow method
Autorzy:
Kowalska, J
Wróblewski, E.
Powiązania:
https://bibliotekanauki.pl/articles/317153.pdf
Data publikacji:
2016
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
metoda ZeroFlow
azotowanie
pierścienie tłokowe
ZeroFlow method
nitrification
piston rings
Opis:
W artykule omówiona została nowoczesna metoda regulowanego azotowania gazowego, nazywana ZeroFlow, która wykorzystywana jest do azotowania części silników spalinowych. Wzrastająca wydajność silników spalinowych powoduje, że silniki te pracują w warunkach dużych obciążeń cieplnych i mechanicznych, co jest zdecydowanie niekorzystnym zjawiskiem – zwłaszcza dla elementów układu tłokowo-korbowego, takich jak wały korbowe czy pierścienie tłokowe. Wysokie temperatury i ciśnienia panujące w cylindrze podczas procesu spalania powodują, iż pierścienie pracują w warunkach obciążeń dopuszczalnych; dlatego też głównym założeniem w ich konstrukcji jest wysoka wytrzymałość oraz odporność na zużycie ścierne. Jedną z metod podwyższenia odporności na zużycie czy korozję oraz podniesienia wytrzymałości zmęczeniowej powierzchni pierścieni, cieszącą się rosnącym zainteresowaniem przemysłu motoryzacyjnego, jest azotowanie, a dokładniej – regulowane azotowanie gazowe. Azotowanie stali z wykorzystaniem metody ZeroFlow umożliwia precyzyjne kształtowanie warstw azotowanych o określonej budowie fazowej, wymaganych grubościach występujących w niej stref oraz wymaganych rozkładach twardości. Oznacza to, że warstwa taka spełnia wszystkie stawiane jej wymagania, dzięki czemu zwiększa trwałość azotowanych detali, a co za tym następuje – trwałość eksploatacyjną maszyn i pojazdów. W artykule przedstawiono nie tylko wymagania stawiane pierścieniom tłokowym, wynikające z ich warunków pracy, ale również zaprezentowano przykład azotowania pierścieni tłokowych przy użyciu metody ZeroFlow oraz omówiono wyniki badań metalograficznych.
Paper presents new method of controlled gas nitriding called ZeroFlow, which is used for nitriding of internal combustion engine parts. Increasing efficiency of internal combustion engines means that engines are working under high thermal and mechanical loads, which is the unfavorable phenomenon – especially for elements of engine power train such as crankshaft or piston rings. On account of high temperatures and pressures in the cylinder during combustion, piston rings work under the conditions of limit load; therefore, the main assumption in their construction is to ensure high strength and abrasive wear resistance. Heat treatment is the most common way used for improving tribological properties of piston rings; one of the methods of heat treatment using in automotive industry which meets with growing interest is nitriding, or more precisely – controlled gas nitriding. Steel nitriding using the ZeroFlow method allows precise forming of nitrided layers with respect to the phase structure, zone thicknesses and hardness distribution, which means that nitrided layer obtained on piston rings fulfil the requirements imposed on them, and as a consequence – it allows to achieve the appropriate durability of each part. This article discuss not only the requirements connected with nitrided layer on piston rings, but also shows the industrial example of nitriding piston rings using ZeroFlow method and presents results of metallographic tests.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2016, 17, 12; 1082-1087
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid computer system for the identification of metallic material models on the basis of laboratory experiments
Autorzy:
Rauch, Ł.
Górecki, G.
Pietrzyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/305778.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
inverse analysis
identification of model parameters
computer system
rings compression
Opis:
The identification of the proper parameters of material models plays a crucial role in the design of production technologies, especially in the case of modern materials with diversified properties under different boundary conditions. The procedure of identification is usually based on an optimization algorithm that uses sophisticated numerical simulations as a part of the goal function and compares the obtained results with experimental tests. Despite its reliability, such an approach is numerically inefficient. This paper presents the concept of how to replace the most numerically-demanding part of the identification procedure with metamodels, allowing us to maintain uniform result quality. The computer system, which allows us to manage input data, metamodels, and calculations, is proposed and described in detail in this paper. Finally, the proposed approach is validated on the basis of tests performed in the laboratory.
Źródło:
Computer Science; 2016, 17 (2); 123-143
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of engine load on piston ring pack operation of a marine two - stroke engine
Autorzy:
Wolff, A.
Powiązania:
https://bibliotekanauki.pl/articles/246695.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
marine engines
piston rings
gas dynamics
hydrodynamic lubrication
mixed friction
Opis:
A set of piston rings is used to form a dynamic gas seal between the piston and cylinder wall. Many physical phenomena are associated with the operation of the system piston-ring-cylinder (PRC), such as: inter-ring gas dynamics for the labyrinth seal, hydrodynamic lubrication and mixed friction in gaps between the rings and cylinder liner, oil flow and distribution of lubricant along the liner, twist motion of rings, liner temperature influence on the oil viscosity. A complex model of the PRC system has been developed by the author. Among own models it includes several sub-models taken from literature, like: a model of viscous oil flow between rough gap surfaces formulated by Patir and Cheng and an elastic contact model of Greenwood and Tripp. The main parts of the mathematical model and software have been experimentally verified abroad by the author at the marine engine-designing centre. A relatively good qualitative and quantitative compatibility between the experimental measurements and calculated results has been achieved. In contrast to the previous papers of the author, new calculation results for a marine two-stroke engine have been presented. These results concern influence of engine load on piston ring pack operation of the analysed engine. They include basic physical quantities associated with gas and oil flow in the piston-ring-cylinder system of the engine. The developed model can be utilized for: evaluation of gas leakage through the sealing ring set, prediction of lubrication conditions of piston rings and oil consumption, defining areas of the possible cylinder liner wear and profile changes of piston rings sliding surfaces, and thus can be useful for optimization of the PRC system design.
Źródło:
Journal of KONES; 2012, 19, 2; 557-568
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical assessments of selected main engine pistons drawing out records and record of cylinder oil feed rates
Autorzy:
Kamiński, W.
Powiązania:
https://bibliotekanauki.pl/articles/360034.pdf
Data publikacji:
2013
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
cylinder liner wear
piston rings wear
cylinder oil feed rate
Opis:
The paper presents the analytical assessment of main engine piston drawing out records and record of cylinder oil feed rates. Collated and analyzed the wear records of cylinder liners and piston rings of main engines installed in three ships on the basis of the measurements at main engine piston drawing out measured during dry dock main engine overhauls. An analytical data have been taken from operating records. Author presents a summary of the results of these surveys and analytical assessments made for selected three vessels (VLCC) with Main Engines B&W Man MC series.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2013, 36 (108) z. 2; 56-60
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A characterization of weakly J(n)-rings
Autorzy:
Danchev, P. V.
Powiązania:
https://bibliotekanauki.pl/articles/2052406.pdf
Data publikacji:
2018
Wydawca:
Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
Tematy:
Boolean rings
idempotents
units
nilpotents
Jacobson radical
J (n)-rings
pierścień Boole'a
idempotent pierścienia
element idempotentny
jednostki
nilpotent pierścienia
element nilpotentny
rodnik Jacobsona
Opis:
A ring $R$ is called a J(n)-ring if there exists a natural number $n \geq 1$ such that for each element $r \in R$ the equality $r^{n+1} = r$ holds and a weakly J(n)-ring if there exists a natural number $n \geq 1$ such that for each element $r \in R$ the equalities $r^{n+1} = r$ or $r^{n+1} = -r$ hold. We completely describe both classes of these rings R for any n, thus considerably extending some well-known results in the subject, especially that of V. Perić in Publ. Inst. Math. Beograd (1983) as well as, in particular, the classical description of Boolean rings when n = 1.
Źródło:
Journal of Mathematics and Applications; 2018, 41; 53-61
1733-6775
2300-9926
Pojawia się w:
Journal of Mathematics and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania biologiczne warstw powierzchniowych w aspekcie zastosowania na pierścień zastawki serca
Biological properties of surface layers for ring of heart valve application
Autorzy:
Gonsior, M.
Kustosz, R.
Borowski, T.
Ossowski, M.
Sanak, M.
Jakiełła, B.
Czarnowska, E.
Wierzchoń, T.
Powiązania:
https://bibliotekanauki.pl/articles/285447.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
zastawka serca
sztuczna komora serca
POLVAD
heart valve
heart valve rings
Opis:
Oryginalna sztuczna komora wspomagania serca POLVAD opracowana w Polsce, została zastosowana dotychczas w leczeniu ponad 210 pacjentów. Najdłuższe wspomaganie serca za pomocą komory POLVAD trwało ponad rok. Dla protezy tej opracowywana jest innowacyjna zastawka dyskowa, z nisko profilowym pierścieniem wykonanym ze stopu tytanu. Dla zminimalizowania trombogenności pierścienia zastawki opracowano dyfuzyjne warstwy powierzchniowe: azotowaną typu TiN+Ti2N+αTi(N) i tlenoazotowaną typu TiO2+TiN+Ti2N+αTi(N), wytwarzane obróbką jarzeniową na potencjale plazmy. Trombogenność różnych kompozycji warstw została porównana w aspekcie aktywacji i adhezji płytek krwi do powierzchni biomateriału. Oceniono również wpływ metody sterylizacji biomateriału na intensywność adhezji trombocytów do jego powierzchni. Warstwy TiN oraz TiO2wykazały najniższą trombogenność, przy czym dla warstwy TiN korzystniejsza jest sterylizacja gazowa, podczas gdy dla warstwy TiO2- sterylizacja plazmowa.
The original ventricular assist device POLVAD developed in Poland was used in over 210 patients so far. The longest POLVAD heart assistance excided one year. The innovative tilting disk valve with low profile ring made of titanium is developed for POLVAD. To minimize the valve ring thrombogenicity the diffusive surface layers were manufactured: nitriding TiN+Ti2N+αTi(N) and oxynitriding TiO2+TiN+Ti2N+αTi(N), in the glow discharge process on the plasma potential level. The thrombogenicity of different layers compositionwas compared regarding platelets activation and platelets adhesion to the material surface. The influence of material sterilization method on the platelets adhesion intensity was evaluated in addition. The nitriding TiN and oxynitriding TiO2layers have demonstrated the lowest thrombogenicity while the gas sterilization was the most profitable for nitriding layers – TiN and the plasma sterilization for oxynitriding layers – TiO2.
Źródło:
Engineering of Biomaterials; 2011, 14, 102; 15-22
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reducing wear of piston rings using zero flow nitriding
Autorzy:
Kowalska, J.
Wróblewski, E.
Powiązania:
https://bibliotekanauki.pl/articles/243715.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
piston rings
controlled gas nitriding
nitrided layer
diffusion zone
hardness distribution
Opis:
This article presents new method of controlled gas nitriding called ZeroFlow, which is used for nitriding of internal combustion engine parts. Increasing efficiency of internal combustion engines means that engines are working under high thermal and mechanical loads, which is the unfavourable phenomenon – especially for elements of engine power train such as crankshaft or piston rings. Due to the high temperature and pressure in cylinder during combustion, piston rings are working under limit loads, which mean that lengthened fatigue life and wear resistant are of critical importance. Heat treatment is the most common way used for improving tribological properties of piston rings; one of the methods of heat treatment using in automotive industry, which meets with growing interest, is nitriding, especially controlled gas nitriding. The main aim of nitriding is to obtain layer with higher surface hardness, improved fatigue life and corrosion resistance, increased wear resistant and antigallic properties. According to that, this layer increase durability of nitrided parts, and as a result – durability of machines and vehicles. Steel nitriding using the ZeroFlow method allows precise forming of nitrided layers with respect to the phase structure, zone thicknesses and hardness distribution, which means that the ZeroFlow nitriding enable maintenance of full control over the kinetics of the nitrided layer growth. Kinetics of nitrided layer growth allows developing the especially dedicated process with specific parameters, which ensure obtaining on piston rings nitrided layer with strictly defined, required properties.
Źródło:
Journal of KONES; 2016, 23, 2; 193-199
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cyclic changes of climate in Europe during the last millenium according to dendrological data
Autorzy:
Boryczka, Jerzy
Stopa-Boryczka, Maria
Bijak, Szymon
Miłaszewska, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/2029440.pdf
Data publikacji:
2008-06-01
Wydawca:
Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
Tematy:
air temperature
NAO
solar activity
spectrum
periods
tendencies
forecast
tree-rings
Opis:
The paper discusses periodic climate changes in Europe determined on the basis of dendrochronological data dating back one thousand years. In tree-ring width sequences of trees growing in Poland there are approximately 8-, 11-, 100- and 180- year periods. The tree-ring widths of oaks growing in Poland for the last centuries are characterised, without any significant amplitude, by 8- and 11-year periods (Tab. 1). In turn, chronologies of pine, spruce, larch, oak and fir growing in Europe are characterised by 100- and 180-year periods (Tab. 2). Cycles of dendrochronological variables approximate cycles of air temperature and North Atlantic Oscillation NAO as well as those of solar activity. The forecast of annual growth (ring width) for 2001-2100 was calculated by interference of the tree-ring width cycles determined by the sinusoidal regression method. Because of much longer empirical sequences of specific periods, the credibility of forecasts for treering widths is greater than that for air temperature.
Źródło:
Miscellanea Geographica. Regional Studies on Development; 2008, 13; 57-66
0867-6046
2084-6118
Pojawia się w:
Miscellanea Geographica. Regional Studies on Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ruin marble : a record of fracture-controlled fluid flow and precipitation
Autorzy:
Marko, F.
Pivko, D.
Hurai, V.
Powiązania:
https://bibliotekanauki.pl/articles/2058871.pdf
Data publikacji:
2003
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Western Carpathians
fluids
healed joints
Liesegang rings
ruin marble
banded structures
Opis:
The ruin marble structure of the Cretaceous/Paleogene fine-grained marly limestone from the Outer Flysch Belt of the Western Carpathians has a non-tectonic origin, according to structural and sedimentological evidence. Distinctive offsets of coloured red-brownish ferric oxyhydroxide bands are not due to displacements along rock-cutting fractures, as they superficially appear to be. Evidences for shear movement along these pseudo-faults were not observed. Band offsets result from different velocities of pervasively diffusing fluids, precipitating ferric oxyhydroxides in corridors bounded by sets of mineralised systematic joints. During rock weathering, calcite-filled joints operated as barriers for lateral fluid diffusion, but enabled longitudinal diffusion along healed joints. Simple laboratory experiments have been performed to simulate the formation of natural ruin marble structure.
Źródło:
Geological Quarterly; 2003, 47, 3; 241-252
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radar Cross-section Reduction of Planar Absorbers Using Resistive FSS Unit Cells
Autorzy:
Jasim, Mustafa B.
Sayidmarie, Khalil H.
Powiązania:
https://bibliotekanauki.pl/articles/27312944.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
carbon paste
double rings
FSS
radar cross-sectionreduction
rasorber
unit cell
Opis:
This paper demonstrates the feasibility of reducingradar cross-section by employing resistive sheets or rings inthe conducting elements of an FSS unit cell. The idea behindthe approach in question is to create power-absorbing elementswhich may help reduce the power reflected from FSS surface.The investigated FSS unit cells have the form of double-closedrings and double-closed-split rings. A carbon paste, serving asthe resistive layer, was inserted in various regions within the unitcell. The CST Microwave Studio software was used to obtain thereflection coefficient. Specific dimensions and conductivity of thepaste were selected to ensure better performance. Simulationresults showed that the reflection coefficient may be reducedby8dB, to14dB, by using carbon paste with the conventionalcopper layer.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 4; 61--67
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Real values of local resistance coefficients during water flow through a pipe aerator with filling
Autorzy:
Kalenik, Marek
Chalecki, Marek
Wichowski, Piotr
Kiczko, Adam
Chmielowski, Krzysztof
Świętochowska, Martyna
Gwoździej-Mazur, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/28411645.pdf
Data publikacji:
2023
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
Bialecki rings
local resistance coefficient
pipe aerator
pressure difference
volumetric water flow
Opis:
The paper presents the results of studies on local resistance coefficients (ζ). The study used pipe aerators with filling made according to the Polish patent PL235924. The hydraulic investigations were performed in real working conditions of a water treatment plant in a testing rig built in the Scientific and Research Water Station of the Warsaw University of Life Sciences (SGGW). The investigation encompassed two plastic pipe aerators of an internal diameter 101.6 and 147.6 mm with steel Białecki rings of 12 and 25 mm in diameter. Measurements of pressure difference (Δp) in the investigated aerators were performed at volumetric water flows (Q) selected from the range 2-20 m3∙h-1 with the interval 2 m3∙s-1. The values of ζ were determined according to the PN-EN 1267:2012 standard. The investigation showed that the ζ depends both on an internal diameter of the plastic pipe aerator and the diameter of Białecki steel rings. The values of ζ increase with a decrease of the internal diameter of the pipe aerator and a decrease of the ring diameter.
Źródło:
Journal of Water and Land Development; 2023, 59; 174--182
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The method of determining of transmission properties of networks based on regular graphs topology
Metoda badania właściwości transmisyjnych sieci o topologii grafów regularnych
Autorzy:
Ledziński, D.
Śmigiel, S.
Śrutek, M.
Marchewka, A.
Powiązania:
https://bibliotekanauki.pl/articles/389780.pdf
Data publikacji:
2014
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydawnictwo PB
Tematy:
network
chordal rings
graph
quality
capacity
sieci
pierścienie cięciwowe
graf
jakość
wydajność
Opis:
The paper presents a methodology of study the properties of the transmission networks modeled by 3’rd and 4’th degree chordal rings, developed by the authors. Research methodology is based on two kinds of tests. First of them, measured the amount of data transmitted in different network structures using the HTTP protocol. The second, was measured quality of the received video stream, by the SSIM (Structural similarity) method. For testing, the set of virtual machines, connected by virtual network of 3rd and 4th chordal rings topology were used.
W artykule zaprezentowano opracowaną przez autorów metodykę badania własności transmisyjnych sieci modelowanych przy pomocy grafów cięciwowych trzeciego i czwartego stopnia. W tym celu użyto dwóch testów. Jeden z nich polegał na pomiarze ilości danych przesyłanych w różnych strukturach sieciowych przy pomocy protokołu HTTP, natomiast w drugim mierzona była jakość odebranych obrazów w strumieniach video metodą porównawczą SSIM (Structural SIMilarity). Testy były wykonane według opracowanej przez autora koncepcji polegającej na wykorzystaniu zbioru maszyn wirtualnych połączonych pomiędzy sobą wirtualną siecią o topologii pierścieni cięciwowych trzeciego i czwartego stopnia.
Źródło:
Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy; 2014, 18; 11-22
1899-0088
Pojawia się w:
Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Referential graphs
Grafy referencyjne
Autorzy:
Ledziński, D.
Marciniak, B.
Śrutek, M.
Powiązania:
https://bibliotekanauki.pl/articles/389824.pdf
Data publikacji:
2013
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydawnictwo PB
Tematy:
graphs
chordal rings
data communication networks
grafy
grafy referencyjne
projektowanie sieci telekomunikacyjnych
Opis:
The authors of this paper have defined the notion of referential graphs which allow to model data and telecommunication networks in order to optimize them. Parameters of this type of graphs can be compared with parameters of modified chordal rings three and four degree. A description of the program developed for graphs of this type and its effects have been presented.
W artykule zdefiniowano pojęcie Grafu Referencyjnego, za pomocą którego można modelować sieci teleinformatyczne w celu ich optymalizacji. Zdefiniowano parametry takiego typu grafów, które zostały porównane z parametrami modyfikowanych pierścieni cięciwowych trzeciego i czwartego stopnia. Do modelowania poszczególnych przypadków opracowano program symulacyjny. Zaprezentowano opis tego programu oraz wyniki otrzymane przy wyszukiwaniu grafów referencyjnych dla szerokiego spektrum danych wejściowych.
Źródło:
Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy; 2013, 17; 37-73
1899-0088
Pojawia się w:
Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza ruchów pierścieni uszczelniających w aspekcie zachowania szczelności złożenia tłok : pierścienie : cylinder
Analysis of the movement of the sealing rings in terms of preserving the tightness of the piston : ring : cylinder assembly
Autorzy:
Abramek, K. F.
Klyus, O.
Powiązania:
https://bibliotekanauki.pl/articles/314856.pdf
Data publikacji:
2017
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
tłok
pierścienie
przedmuchy gazów
silnik spalinowy
piston
rings
blow-by
combustion engine
Opis:
Tematyka publikacji dotyczy zagadnień i badań związanych ze zjawiskiem strat ładunku w postaci przedmuchów gazów do skrzyni korbowej przez układ tłok – pierścienie – cylinder (TPC) silników spalinowych. Analizowany problem dotyczy oceny możliwości ruchów i przemieszczeń pierścieni uszczelniających, co w największym stopniu wpływa na wartość natężenia przedmuchów. W wyniku przeprowadzonych badań silników zauważono, że zjawisko przedmuchów zależy od wielu parametrów konstrukcyjnych, jak i eksploatacyjnych tłokowego silnika spaliowego. Przeprowadzony zakres badań potwierdził wpływ tych parametrów na ruchy pierścieni i na zjawisko przedmuchów.
The subject of the publication concerns issues and research related to the phenomenon of cargo losses in the form of gusts of crankcase gases through the piston-ring-cylinder (PRC) of internal combustion engines. The analyzed problem concerns the evaluation of the movement and displacement of the sealing rings, which has the greatest effect on the purge rate. As a result of engine tests, it has been observed that the blow-by phenomenon is influenced by many constructional and operational parameters of the piston-type combustion engine. The scope of the study confirmed the influence of these parameters on the ring motions and on the blow-by phenomenon.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2017, 18, 7-8; 143-147
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of the distribution of variable characteristics determining the asymmetry of the sealing rings sliding surfaces on the values of friction loss coefficients and other selected parameters of oil film
Autorzy:
Wróblewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/133559.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
rings asymmetrical sliding surface
friction loss
oil film
straty tarcia
film olejowy
Opis:
The article presents the results of research on the effect of the change in coordinates that determine the location of the common vertex of the parabolas and ellipses demonstrating the asymmetric shape of the rings sliding surfaces on the change in the thickness of oil film, the amount of scraped oil, and the oil left on the cylinder wall, once a set of selected sealing rings has passed, as well as the results concerning friction losses. Mathematical relationships of the asymmetric shapes of the rings sliding surfaces were presented, and the values of coefficients characterizing selected parameters of oil film and friction losses were determined. It was confirmed that there is a large dependence of the coordinate values of the vertices determining the asymmetric shapes of these surfaces on the condition and cooperation between piston rings and the cylinder bearing surface, and mainly on the amount of the oil scraped in the selected engine strokes.
Źródło:
Combustion Engines; 2017, 56, 4; 107-116
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MoS2/WS2/FineLPN Composite Layers – a New Approach to Low Frictional Coatings for Piston Rings
Warstwy kompozytowe MoS2/WS2/FineLPN – nowe podejście do powłok o niskim tarciu na pierścienie tłokowe
Autorzy:
Kula, Piotr
Pietrasik, Robert
Pawęta, Sylwester
Komorowski, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/2171809.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
piston rings
nitriding
low friction
wear
pierścienie tłokowe
azotowanie
warstwa niskotarciowa
zużycie
Opis:
In the search for alternative processes of technologically difficult and environmentally dangerous galvanic chromium coatings on cast iron piston rings, composite coatings of low-friction nanoparticles MoS2, WS2and/or rGO embedded in a hard matrix of iron nitrides have been investigated. Laboratory tribological and operational tests on a real aircraft engine have been carried out to select the optimal technological parameters and microstructures of low frictional layers. A dry friction coefficient of 0.13 has been obtained for the best of the processes, i.e., four times lower than for raw reference samples (0.55). According to that technological option, the low-friction layers were produced for a set of rings for three cylinders of a Boxer aircraft engine and tested comparatively in an operational test with the rings in the other three cylinders. The experimental engine has passed the operational test obtaining the assumed power performance, fuel consumption and admission criteria of exhaust purity and oil purity.
W poszukiwaniu alternatywnych procesów dla trudnych technologicznie i niebezpiecznych dla środowiska galwanicznych powłok chromowych na żeliwnych pierścieniach tłokowych badano powłoki kompozytowe z niskotarciowych nanocząstek MoS2, WS2 i/lub rGO osadzonych w twardej osnowie z azotków żelaza. Przeprowadzono laboratoryjne badania tribologiczne oraz próby eksploatacyjne na rzeczywistym silniku lotniczym w celu doboru optymalnych parametrów technologicznych i mikrostruktur warstw o niskim współczynniku tarcia. Dla najlepszego z procesów uzyskano współczynnik tarcia suchego na poziomie 0,13, czyli czterokrotnie niższy niż dla surowych próbek referencyjnych (0,55). Zgodnie z tą opcją technologiczną wytworzono warstwy o niskim współczynniku tarcia dla zespołu pierścieni do trzech cylindrów silnika lotniczego Boxer i przetestowano je porównawczo w próbie eksploatacyjnej z pierścieniami chromowanymi w pozostałych trzech cylindrach, uzyskując założone parametry mocy, zużycie paliwa oraz kryteria dopuszczenia czystości spalin i oleju.
Źródło:
Tribologia; 2022, 3; 49--58
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Music emotions and associations in film music listening: The example of leitmotifs from The Lord of the Rings movies
Autorzy:
Chełkowska-Zacharewicz, Maria
Paliga, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/2125137.pdf
Data publikacji:
2020-01-10
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II. Towarzystwo Naukowe KUL
Tematy:
film music
leitmotif
music-induced emotions
affect
The Lord of the Rings
Opis:
The aim of the present study was to investigate which musical emotions and associations appeared while listening to leitmotifs in film music. A sample of 157 participants took part in the study, in which musical associations and emotions were analysed in relation to seven groups of musical themes from The Lord of the Rings films (LOTR). The LOTR soundtrack is a good example of the use of symbols in music to represent ideas, characters, etc. The results show that both the respondents’ associations and the musical emotions they experienced were related to the characteristics of musical motifs. The results are discussed in relation to the assumed features of musical motifs composed by Howard Shore.
Źródło:
Roczniki Psychologiczne; 2019, 22, 2; 151-175
1507-7888
Pojawia się w:
Roczniki Psychologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
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