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Konstrukcyjne przyczyny niepowtarzalności pracy systemów opartych na ogniwach paliwowych typu PEM

100%

Małek A. , Gęca M.

Combustion Engines

2013

tom R. 52, nr 3

449--452

W artykule przedstawiono konstrukcyjne przyczyny niepowtarzalności pracy ogniw paliwowych, które są wynikiem natury zjawisk zachodzących w ogniwach paliwowych, zastosowanych materiałów oraz dokładności wykonania poszczególnych elementów systemu. Szczegółowo opisano problem migracji wody przez membranę PEM, tworząc jego matematyczny model oraz sposób radzenia sobie z nim. Stosując analizę diagramów rekurencyjnych oraz analizę statystyczną poszczególnych serii czasowych pokazano znaczące różnice w dynamice pracy ogniwa paliwowego z różnymi poziomami obciążeń prądowych. Wykazano także potencjalny wpływ niepowtarzalności pracy ogniw na sterowanie tym, jeszcze nie do końca poznanym obiektem.

The paper presents the constructional reasons for the non-repeatability of fuel cells operation, which result from the nature of the phenomena occurring in fuel cells, used materials and the accuracy of the assembling of individual system components. This paper describes in detail also the issue of water migration through the PEM membrane, creating its mathematical model and a way of its solving. Using recurrence plot analysis and statistical analysis of individual time series shows significant differences in the dynamics of fuel cell operation with different levels of current load were presented. The potential impact of the non-repeatability of fuel cell operation on controlling this already unexplored type of fuel cell is demonstrated.

Effect of depth surface defects in carbon fibre reinforced composite material on the selected recurrence quantifications

100%

Ciecieląg K. , Kęcik K. , Zaleski K.

tom Vol. 20, nr 2(64)

71--80

The paper discusses the problem of possibility of the detecting surface defects in carbon fibre reinforced plastics (CFRP) materials on the basis of the milling time series. First, the special defects in the hole-shaped with various depth were made. Next, the cutting forces are measured during the milling machining. Finally, the recurrence plot and quantification analysis was applied. The obtained results show that the depth defect influences the selected recurrence quantifications, which can be used as the simple defect indicators. The conducted research allow to determine the percentage share of the detectable defects. The novelty of the work and an unresolved problem is the selection of recurrence quantifications with the simultaneous use of them to detect the size of defects in carbon fibre reinforced plastics.

The use of recurrence plots and beat recordings in chronic heart failure detection

67%

Lewenstein K. , Jamroży M. , Leyko T.

2016

tom Vol. 64, nr 2

339--345

Chronic heart failure is a syndrome consisting in clinical symptoms that arise as a result of complications of many disease entities. According to the definition it is a condition in which, as a consequence of permanent heart dysfunction, cardiac output is reduced in relation to tissues’ metabolic demand. This results in subjective symptoms or proper cardiac output is sustained over higher filling pressure of the left heart ventricle. The occurrence of disease among adults in Europe and North America is 0.4-2%. Heart dysfunction detected by echocardiography appears with the frequency of 3%, and in people over 60 years of age it doubles with each decade of life, reaching 10% after 80 years of age. The aim of the study is to make an acquisition of fremitus in apex beat place and quantitative evaluation of some of their features which are correlated with the advanced syndrome. We have built the apparatus for the heart signal recording and proposed the original method of its analysis based on the theory of chaos and recurrence plots. It gave us, on the group of 85 patients, sensitivity equal to 0.896 specificity equal to 0.676 and the accuracy of diagnostics of the chronic heart failure equal up to 80%.