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1

Improving the Accuracy of Fatigue Damage Calculations for Archived Data

Leski Andrzej

Fatigue of Aircraft Structures

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2019

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Iss. 11

113--120

EN

Historical operational usage data give a ground for fatigue damage estimation. Quality of sensors and recorders two or more decades ago were lower then modern one. Lack of resolution in nz-level measurement and recording leads to some errors in fatigue damage calculations. In this paper author propose a method to improve the accuracy of fatigue damage calculations for archived data. The method takes advantage of typical distribution of accumulated cycles for aircrafts. Small correction in representative nz value taken in calculations can reduce the error in fatigue damage assessment.

2

Minimal κ-connected Graphs with Small Number of Vertices of Degree κ

Karpov D. V.

Fundamenta Informaticae

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2016

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Vol. 145, nr 3

279--312

3

The effect of carbonate aggregate reaction in cement concrete on long-term changes in strength due to corrosion exposition conditions

Dębska D.

Ochrona przed Korozją

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2015

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nr 5

185--189

EN

The results of a study on the impact of defined environmental exposition such as H2O, MgSO4, Na2SO4 in different temperature condition on the susceptibility to dedolomitisation processes of cement concrete with selected dolomite aggregate with specific regard to changes in long-term strength properties are presented in the paper. The impact of defined liquid environment containing different amount of calcium and magnesium ions in various temperature condition on a susceptibility to release Ca2+ and Mg2+ ions caused by chemical reaction with examined aggregate was indicated too.

PL

W artykule przedstawiono wyniki badań wpływu zdefiniowanych warunków ekspozycji korozyjnej, takich jak H2O, MgSO4, Na2SO4 i zróżnicowanej temperatury, na podatność na procesy związane z dedolomityzacją betonu cementowego z kruszywem dolomitowym. Jako cechy diagnostyczne przyjęto zmiany wytrzymałości na zginanie i ściskanie. Przedstawiono również wyniki badań wpływu środowiska ciekłego zawierającego ściśle określoną zawartość jonów wapnia i magnezu oddziałującego w różnych warunkach temperatury na reaktywność kruszywa powodującą uwalnianie jonów Ca2+ i Mg2+.

4

Analiza, modelowanie oraz prognozowanie stanu i rozwoju kryzysowej sytuacji socjalno-politycznej : pewne rozważania wstępne

Kurbanowicz-Ramazanow S., Stemplewska L.

Studia i Materiały / Europejska Uczelnia Informatyczno-Ekonomiczna w Warszawie

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2014

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Nr 2(8)

77--100

PL

W pracy po raz pierwszy przedstawiono pewne rozważania wstępne dotyczące analizy i modelowania stanu socjalno-politycznego głębokiego kryzysu na podstawie supersystemu typu „Majdan”. Pokazano możliwość stosowania podejścia entropii i zaprezentowano jedno ogólne podejście budowy integralnego nieliniowego dynamicznego modelu interakcji w złożonym systemie o wielu agentach typu „Majdan” na podstawie równania logistycznego oraz jego szczególne przykłady.

EN

This paper presents some preliminary considerations on the analysis and modeling of socio-political state of deep crisis based on “Maidan” supersystem. The possibility of using entropy approach is shown and a general approach of building an integral nonlinear dynamic model of interaction in a complex system with multiple agents of “Maidan” type based on the logistic equation is presented as well as its specific examples.

5

Residual Closeness in Cycles and Related Networks

Odabaş Z. N., Aytaç A.

Fundamenta Informaticae

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2013

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Vol. 124, nr 3

297--307

EN

Networks are known to be prone to node or link failures. A central issue in the analysis of networks is the assessment of their stability and reliability. The main aim is to understand, predict, and possibly even control the behavior of a networked system under attacks or disfunctions of any type. A central concept that is used to assess stability and robustness of the performance of a network under failures is that of vulnerability. A network is usually represented by an undirected simple graph where vertices represent processors and edges represent links between processors. Different approaches to properly define a measure for graph vulnerability has been proposed so far. In this paper, we study the vulnerability of cycles and related graphs to the failure of individual vertices, using a measure called residual closeness which provides a more sensitive characterization of the graph than some other well-known vulnerability measures.

6

Stratigraphy and sedimentology of the Niger Delta

Reijers T. J. A.

Geologos

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2011

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Vol. 17, No. 3

133--162

EN

During the Cenozoic, until the Middle Miocene, the Niger Delta grew through pulses of sedimentation over an oceanward-dipping continental basement into the Gulf of Guinea; thereafter progradation took place over a landward-dipping oceanic basement. A 12,000 m thick succession of overall regressive, of flapping sediments resulted that is composed of three diachronous siliciclastic units: the deep-marine pro-delta Akata Group, the shallow-marine delta-front Agbada Group and the continental, delta-top Benin Group. Regionally, sediment dispersal was controlled by marine transgressive/regressive cycles related to eustatic sea-level changes with varying duration. Differential subsidence locally influenced sediment accumulation. Collectively, these controls resulted in eleven chronostratigraphically confined delta-wide megasequences with considerable internal lithological variation. The various sea-level cycles were in or out of phase with each other and with local subsidence, and interfered with each other and thus influenced the depositional processes. At the high inflection points of the long-term eustatic sea-level curve, floodings took place that resulted in delta-wide shale markers. At the low inflection points, erosional channels were formed that are often associated, downdip, with turbidites in low-stand sediments (LSTs). The megasequences contain regional transgressive claystone units (TST) followed by a range of heterogeneous fine-to-coarse progradational or aggradational siliciclastic (para)sequence sets formed during sea-level high-stand (HST). An updated biostratigraphic scheme for the Niger Delta is presented. It also updates a sedimentation model that takes into consideration local and delta-wide effects of sea-level cyclicity and delta tectonics. Megasequences were formed over time intervals of ~5 Ma within individual accurate megastructures that laterally linked into depobelts. The megasequences form the time-stratigraphic frame of the delta and are the backbone for the new delta-wide lithostratigraphy proposed here. Such a new lithostratigraphy is badly needed, in particular because of the vigorous new activity in the offshore part of the Niger Delta (not covered in this contribution). There, as well as in the onshore part of the delta, the traditional lithostratigraphic subdivision of the Cenozoic Niger Delta section into three formations is insufficient for optimum stratigraphic application; moreover, the various informal subdivisions that have been proposed over time are inconsistent.

7

Proof-graphs: a Thorough Cycle Treatment, Normalization and Subformula Property

Alve G.V., Oliveira A.G.,de, Queiroz R., de

Fundamenta Informaticae

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2011

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Vol. 106, nr 2-4

119-147

EN

A normalization procedure is presented for a classical natural deduction (ND) proof system. This proof system, called N-Graphs, has a multiple conclusion proof structure, where cycles are allowed. With this, we have developed a thorough treatment of cycles, including cycles normalization via an algorithm. We also demonstrate the usefulness of the graphical framework of N-Graphs, where derivations are seen as digraphs. We use geometric perspective techniques to establish the normalization mechanism, thus giving a direct normalization proof. Moreover, the subformula and separation properties are determined.

8

Cyclability in bipartite graphs

Amar D., Flandrin E., Gancarzewicz G.

Opuscula Mathematica

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2009

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Vol. 29, no. 4

345-364

EN

Let G = (X, Y; E) be a balanced 2-connected bipartite graph and S ⊂ V(G). We will say that S is cyclable in G if all vertices of S belong to a common cycle in G. We give sufficient degree conditions in a balanced bipartite graph G and a subset S ⊂ V(G) for the cyclability of the set S.

9

Regional differences in dynamics of bank vole populations in Europe

Hansson L., Jędrzejewska B., Jędrzejewski W.

Polish Journal of Ecology

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2000

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Vol. 48, Suppl.

163-177

EN

Fluctuation patterns of bank vole populations were reviewed for central and north-western Europe. Many fairly stable populations occur in central and western Europe while clearly cyclic populations, with an interval of 3-4 year between peaks, are typical for northern Fennoscandia. There is a transition zone around 60 stopni N. In forests in central Europe dominated by oak, and less so by beech and lime, bank vole populations demonstrate outbreak dynamics with peaks at 6-9 year intervals, related to mast seeding. Both cyclic and outbreak populations show pronounced annual variations in reproduction and survival. Community conditions are described for these types of populations and annual variations in food supply are denoted. Isolated (island) populations are characterised by generally high densities and high adult survival. Factors that have been suggested to explain the various dynamics differ: predation and food for cyclic performance, food alone for outbreaks and social factors within circumscribed populations.

10

Long-term dynamics of the bank vole Clethrionomys glareolus at Pallasjarvi, northern Finnish taiga

Henttonen H.

Polish Journal of Ecology

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2000

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Vol. 48, Suppl.

87-96

EN

The whole rodent community (eight arvicoline species) has been followed at Pallasjarvi, at the northern limit of Clethrionomys glareolus in Finnish Lapland, since 1970. Dynamics were cyclic until the mid 1980's but since then the pattern has been stable. Also the species abundances have changed. The delayed density dependence, characterising the cyclic period, is not found during the stable period. Causes for this change in cyclicity are discussed. The bank vole is the most common rodent species in forests up to its northern limit. The long-term, Year around live trapping studies and feeding experiments suggest e.g. that delayed maturation of young is not optimal but due to social constraints. Food addition resulted in higher densities, but the effect on the density-dependent structure was negligible and the dynamics were not affected by food addition.