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Tytuł:
Analysis of a nonlinear tuned mass damper by using the multi-scale method
Autorzy:
Liu, Junfeng
Yao, Ji
Huang, Kun
Zhang, Qing
Ze, Li
Powiązania:
https://bibliotekanauki.pl/articles/2104766.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nonlinear characteristics
complex average method
multi-scale method
nonlinear design
control performance
Opis:
A tuned mass damper is a kind of vibration damping device which has been widely used in tall buildings, machinery, bridges, aerospace engineering and other fields. In practical engineering applications, due to large deformation caused by large displacement, errors in engineering constructions and the existence of limit devices, the structure and tuned mass dampers inevitably produce some nonlinear characteristics, but these nonlinearities are often ignored. The results of this study confirm that the nonlinearity of the structure and the mass damper should be considered in the process of optimal frequency design, otherwise there will be a large deviation between the design optimal frequency of the mass damper and the actual optimal frequency. In this paper, nonlinear characteristics of the tuned mass damper and the main structure are considered. The first-order differential equations are obtained by using the complex average method, and the nonlinear equations of the tuned mass damper system are derived by using the multi-scale method. On this basis, the parameters are determined. The numerical results show that the error of the approximate solution method is small in the given example. The nonlinear tuned mass damper with nonlinear design exhibits a better control performance.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 463--477
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of different failure approaches in knotty wood
Autorzy:
Guindos, P.
Powiązania:
https://bibliotekanauki.pl/articles/52443.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
knotty wood
wood
comparison
failure prediction
knot
wood defect
multi-scale modelling
average stress approach
Opis:
This article presents and assesses 64 different ways for predicting the failure onset in knotty wooden beams. The aim is to provide engineers and modellers a generalview of how to evaluate the failure in wooden structural members with knots.The studied criteria included both the conventional point-based and average stress theories. Special attention was paid to the effect of the elements of the woodmesostructure, i.e. knots and fiber deviation, which can generate singular stress concentrations as notches or cracks would do in fracture mechanics. The case study consisted of predicting the failure onset of bending in structural wooden beams.A previously validated finite element model was used in order to compute the heterogeneous stresses. It was found that the knots caused considerable stress singularities so that the size of the average stress theory influenced the failure predictions by up to 23%. However, the variations generated by distinct phenomenologicalcriteria were in general much smaller. The application of the average stress theory in large stress integration volumes is strongly recommended when predicting the failure in wood members.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2014, 57, 193
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Degree of internationalization in mesoeconomic perspective
Koncepcja poziomu internacjonalizacji w perspektywie mezoekonomicznej
Autorzy:
Mroczek-Dąbrowska, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/589581.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Ekonomiczny w Katowicach
Tematy:
Degree of internationalization
Industry
Mesoeconomics
Multi-item scale
Branża
Mezoekonomia
Mierniki wielowymiarowe
Stopień internacjonalizacji
Opis:
Although the degree of internationalization (DOI) is currently a well know concept, it still remains underresearched. It is most frequently cited in terms of firm’s international process, but it is much less applied for other levels of analysis. In this article we aim to propose an index of outward DOI that could be used for industry internationalization. We try to replicate Sullivan’s methodology except for the weights of components that we base on a Delphi study among Polish managers. We rank 73 Polish industries according to a DOI index composed of four single measures.
Mimo iż stopień internacjonalizacji (DOI) jest konceptem powszechnie znanym, wciąż rzadko się stosuje badania z jego wykorzystaniem w praktyce. Najczęściej wykorzystuje się go przy badaniu procesu internacjonalizacji przedsiębiorstw, jednak zdecydowanie rzadziej w przypadku rozważań nad innymi poziomami analizy (w tym branżowej). Celem niniejszej publikacji jest, opierając się na osiągnięciach Sullivana, stworzenie indeksu zewnętrznej internacjonalizacji branży. Wagi indeksu zostały przypisane na podstawie badania metodą delficką. Indeks ten został następnie wyliczony dla 73 branż polskiej gospodarki.
Źródło:
Studia Ekonomiczne; 2016, 286; 96-106
2083-8611
Pojawia się w:
Studia Ekonomiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detecting objects using Rolling Convolution and Recurrent Neural Network
Autorzy:
Huang, WenQing
Huang, MingZhu
Wang, YaMing
Powiązania:
https://bibliotekanauki.pl/articles/226942.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multi-scale features
global context information
rolling convolution
recurrent neural network
Opis:
At present, most of the existing target detection algorithms use the method of region proposal to search for the target in the image. The most effective regional proposal method usually requires thousands of target prediction areas to achieve high recall rate.This lowers the detection efficiency. Even though recent region proposal network approach have yielded good results by using hundreds of proposals, it still faces the challenge when applied to small objects and precise locations. This is mainly because these approaches use coarse feature. Therefore, we propose a new method for extracting more efficient global features and multi-scale features to provide target detection performance. Given that feature maps under continuous convolution lose the resolution required to detect small objects when obtaining deeper semantic information; hence, we use rolling convolution (RC) to maintain the high resolution of low-level feature maps to explore objects in greater detail, even if there is no structure dedicated to combining the features of multiple convolutional layers. Furthermore, we use a recurrent neural network of multiple gated recurrent units (GRUs) at the top of the convolutional layer to highlight useful global context locations for assisting in the detection of objects. Through experiments in the benchmark data set, our proposed method achieved 78.2% mAP in PASCAL VOC 2007 and 72.3% mAP in PASCAL VOC 2012 dataset. It has been verified through many experiments that this method has reached a more advanced level of detection.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 2; 293-301
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabric Defect Detection and Classifier via Multi-Scale Dictionary Learning and an Adaptive Differential Evolution Optimized Regularization Extreme Learning Machine
Wykrywanie defektów tkaniny i ich klasyfikacja poprzez zastosowanie maszyny uczącej się (ADE-RELM)
Autorzy:
Zhou, Zhiyu
Wang, Chao
Gao, Xu
Zhu, Zefei
Hu, Xudong
Zheng, Xiao
Jiang, Likai
Powiązania:
https://bibliotekanauki.pl/articles/233999.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
defect detection
multi-scale dictionary learning
regularisation extreme learning machine
adaptive differential evolution
defekty tkaniny
skuteczność wykrywania defektów
maszyna ucząca się
Opis:
To develop an automatic detection and classifier model for fabric defects, a novel detection and classifier technique based on multi-scale dictionary learning and the adaptive differential evolution algorithm optimised regularisation extreme learning machine (ADE-RELM) is proposed. Firstly in order to speed up dictionary updating under the condition of guaranteeing dictionary sparseness, k-means singular value decomposition (KSVD) dictionary learning is used. Then multi-scale KSVD dictionary learning is presented to extract texture features of textile images more accurately. Finally a unique ADE-RELM is designed to build a defect classifier model. In the training ADE-RELM classifier stage, a self-adaptive mutation operator is used to solve the parameter setting problem of the original differential evolution algorithm, then the adaptive differential evolution algorithm is utilised to calculate the optimal input weights and hidden bias of RELM. The method proposed is committed to detecting common defects like broken warp, broken weft, oil, and the declining warp of grey-level and pure colour fabrics. Experimental results show that compared with the traditional Gabor filter method, morphological operation and local binary pattern, the method proposed in this paper can locate defects precisely and achieve high detection efficiency.
W celu opracowania automatycznego modelu wykrywania i klasyfikowania defektów tkanin, zaproponowano nowatorską technikę wykrywania i klasyfikowania opartą na zastosowaniu maszyny uczącej się (ADE-RELM). Proponowana metoda ma na celu wykrywanie powszechnych defektów, takich jak przerwana osnowa i wątek oraz zabrudzenia po oleju. Wyniki eksperymentalne pokazują, że w porównaniu z tradycyjną metodą filtrów Gabora, operacją morfologiczną i lokalnym wzorcem binarnym, proponowana w artykule metoda pozwala na precyzyjne zlokalizowanie defektów i osiąga wysoką skuteczność ich wykrywania.
Źródło:
Fibres & Textiles in Eastern Europe; 2019, 1 (133); 67-77
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis of me marine diesel engine fuel injector with novel IRCMDE method
Autorzy:
Shi, Qingguo
Hu, Yihuai
Yan, Guohua
Powiązania:
https://bibliotekanauki.pl/articles/34608122.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine diesel engine
fuel injector
improved refined composite multi-scale dispersion entropy
fault diagnosis
Opis:
As an important component of the fuel injection system, the fuel injector is crucial for ensuring the power, economy, and emissions for a whole ME (machine electronically-controlled) marine diesel engine. However, injectors are most prone to failures such as reduced pressure at the opening valve, clogged spray holes and worn needle valves, because of the harsh working conditions. The failure characteristics are non-stationary and non-linear. Therefore, to efficiently extract fault features, an improved refined composite multi-scale dispersion entropy (IRCMDE) is proposed, which uses the energy distribution of sampling points as weights for coarse-grained calculation, then fast correlation-based filter (FCBF) and support vector machine (SVM) are used for feature selection and fault classification, respectively. The experimental results from a MAN B&W 6S35ME-B9 marine diesel engine show that the proposed algorithm can achieve 92.12% fault accuracy for injector faults, which is higher than multiscale dispersion entropy (MDE), refined composite multiscale dispersion entropy (RCMDE) and multiscale permutation entropy (MPE). Moreover, the experiment has also proved that, due to the double-walled structure of the high-pressure fuel pipe, the fuel injection pressure signal is more accurate than the vibration signal in reflecting the injector operating conditions.
Źródło:
Polish Maritime Research; 2023, 3; 96-110
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of a boundary perforation on the Dirichlet energy
Autorzy:
Dambrine, M.
Vial, G.
Powiązania:
https://bibliotekanauki.pl/articles/970142.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
pochodna kształtu
pochodna topologiczna
singular shape perturbation
shape derivatives
topological derivatives
multi-scale asymptotic expansion
Opis:
We consider some singular perturbations of the boundary of a smooth domain. Such domain variations are not differentiable within the classical theory of shape calculus. We mimic the topological asymptotic and we derive an asymptotic expansion of the shape function in terms of a size parameter. The two-dimensional case of the Dirichlet energy is treated in detail. We give a full theoretical proof as well as a numerical confirmation of the results.
Źródło:
Control and Cybernetics; 2005, 34, 1; 117-136
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of crack resistance in epoxy/boron nitride nanotube nanocomposites based on multi-scale methodInvestigation of crack resistance in epoxy/boron nitride nanotube nanocomposites based on multi-scale method
Autorzy:
Hemmatian, Hossein
Zamani, Mohammad Reza
Jam, Jafar Eskandari
Powiązania:
https://bibliotekanauki.pl/articles/280181.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
boron nitride nanotube
epoxy
fracture modes
finite element model
multi-scale method
Opis:
Boron nitride nanotubes (BNNTs) possess superior mechanical, thermal and electrical properties and are also suitable for biocomposites. These properties make them a favorable reinforcement for nanocomposites. Since experimental studies on nanocomposites are timeconsuming, costly, and require accurate implementation, finite element analysis is used for nanocomposite modeling. In this work, a representative volume element (RVE) of epoxy/BNNT nanocomposites based on multi-scale modeling is considered. The bonds of BNNT are modeled by 3D beam elements. Also non-linear spring elements are employed to simulate the van der Waals bonds between the nanotube and matrix based on the Lennard- -Jones potential. Young’s and shear modulus of BNNTs are in ranges of 1.039-1.041 TPa and 0.44-0.52 TPa, respectively. Three fracture modes (opening, shearing, and tearing) have been simulated and stress intensity factors have been determined for a pure matrix and nanocomposite by J integral. Numerical results indicate that by incorporation of BNNT in the epoxy matrix, stress intensity factors of three modes decrease. Also, by increasing the chirality of BNNT, crack resistance of shearing and tearing modes are enhanced, and stress intensity factor of opening mode reduced. BNNTs bridge the crack surface and prevent crack propagation.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 1; 207-219
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of the microstructure and properties in the length scales varying from nano- to macroscopic
Autorzy:
Kurzydłowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/199877.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multi length scale modelling
grain boundaries
nanomaterials
Opis:
The aim of this paper is to show the recent progress in multi length scale modelling of the engineering materials. This progress is demonstrated using a series of examples addressing, in particular, the role of effect of the grain boundaries in shaping properties of nano-polycrystalline metals.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 2; 217-226
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-Scale Approach and “Playing Scales” in Economic Geography
Autorzy:
Jakobson, Anatol Jakovlevich
Blinov, Ivan Dmitriyevich
Powiązania:
https://bibliotekanauki.pl/articles/438933.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Pedagogiczny im. Komisji Edukacji Narodowej w Krakowie
Tematy:
multi-scale approach
multiscaleness
playing scales
regional policy
industry location
inter-regional competition
settlement
Opis:
The notions of multiscaleness and “playing scales” are considered for various spheres of economic geography: cartography, settlement geography, toponymics, ethno-historical geography, locating industrial production, touristic promotion, micro-regional (intra-urban) policy. The paper presents the idea of multiscaleness and “playing scales”, as well as the possibility of application of a multi- scale approach in economic geography.
Źródło:
Prace Komisji Geografii Przemysłu Polskiego Towarzystwa Geograficznego; 2014, 27; 211-218
2080-1653
Pojawia się w:
Prace Komisji Geografii Przemysłu Polskiego Towarzystwa Geograficznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-scale curvature tensor analysis of machined surfaces
Autorzy:
Bartkowiak, T.
Brown, C.
Powiązania:
https://bibliotekanauki.pl/articles/1203966.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
curvature tensor
surface metrology
multi-scale geometric characterization
machining
tensor krzywizny
metrologia powierzchni
charakterystyka geometryczna
obróbka
Opis:
This paper demonstrates the use of multi-scale curvature analysis, an areal new surface characterization technique for better understanding topographies, for analyzing surfaces created by conventional machining and grinding. Curvature, like slope and area, changes with scale of observation, or calculation, on irregular surfaces, therefore it can be used for multi-scale geometric analysis. Curvatures on a surface should be indicative of topographically dependent behavior of a surface and curvatures are, in turn, influenced by the processing and use of the surface. Curvatures have not been well characterized previously. Curvature has been used for calculations in contact mechanics and for the evaluation of cutting edges. In the current work two parts were machined and then one of them was ground. The surface topographies were measured with a scanning laser confocal microscope. Plots of curvatures as a function of position and scale are presented, and the means and standard deviations of principal curvatures are plotted as a function of scale. Statistical analyses show the relations between curvature and these two manufacturing processes at multiple scales.
Źródło:
Archives of Mechanical Technology and Materials; 2016, 36; 44-50
2450-9469
Pojawia się w:
Archives of Mechanical Technology and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-scale simulation of hybrid silicon nano-electromechanical (NEM) information systems
Autorzy:
Mizuta, H.
Ramirez, M. A. G.
Tsuchiya, Y.
Nagami, T.
Sawai, S.
Oda, S.
Okamoto, M.
Powiązania:
https://bibliotekanauki.pl/articles/384267.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
multi-scale simulation
NEMS
suspended gate
non-volatile memory
phonon
Opis:
This paper presents emerging NEM hybrid systems for advanced information processing and describes our recent attempts of developing new multi-physics simulation technologies for these NEM systems at micro-, nano- and atomscales.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 4; 58-61
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multifrequency-based non-linear approach to analyzing implied volatility transmission across global financial markets
Autorzy:
Boateng, Ebenezer
Asafo-Adjei, Emmanuel
Gatsi, John Gartchie
Gherghina, Ştefan Cristian
Simionescu, Liliana Nicoleta
Powiązania:
https://bibliotekanauki.pl/articles/19322599.pdf
Data publikacji:
2022
Wydawca:
Instytut Badań Gospodarczych
Tematy:
shocks transmission
information flow
Rényi transfer entropy
multi-scale
market conditions
Opis:
Research background: The contagious impact of the COVID-19 pandemic has heightened financial market's volatility, nonlinearity, asymmetric and nonstationary dynamics. Hence, the existing relationship among financial assets may have been altered. Moreover, the level of investor risk aversion and market opportunities could also alter in the pandemic. Predictably, investors in the heat of the moment are concerned about minimizing losses. In order to determine the level of hedge risks between implied volatilities in the COVID-19 pandemic through information flow, it is required to take into account the increased vagueness of economic projections as well as the increased uncertainty in asset values as a result of the pandemic. Purpose of the article: The study aims to examine the transmission of information between the VIX-implied volatility index for S&P 500 and fifteen other implied volatility indices in the COVID-19 pandemic. Methods: We relied on daily changes in the VIX and fifteen other implied volatility indices from commodities, currencies, and stocks. The study employed the improved complete ensemble empirical mode decomposition with adaptive noise which is in line with the heterogeneous expectations of market participants to denoise the data and extract intrinsic mode functions (IMFs). Subsequently, we clustered the IMFs based on common features into high, low, and medium frequencies. The analysis was carried out using Rényi transfer entropy (RTE), which allowed for the evaluation of both linear and non-linear, as well as varied distributions of the market dynamics. Findings & value added: Findings from the RTE revealed a bi-directional flow of negative information amid the VIX and each of the volatility indices, particularly in the long term. We found this behavior of the markets to be consistent at varying levels of investors' risk aversion. The findings help investors with their portfolio strategies in the time of the pandemic, which has resulted in fluctuating levels of risk aversion. Our findings characterize global financial markets to be "non-linear heterogeneous evolutionary systems". The results also lend support to the emerging delayed volatility of market competitiveness and external shocks hypothesis.
Źródło:
Oeconomia Copernicana; 2022, 13, 3; 699-743
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modelling of hydraulically bonded mixture with rubber admixture due to applied mechanical loadings
Autorzy:
Pietras, D.
Sadowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/391052.pdf
Data publikacji:
2017
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
virtual test
XFEM
FEM
multi-scale modelling
Opis:
Abstract: In this paper the application of the Extended Finite Element Method (XFEM) to anticipate change of the behaviour of composite with complex internal structure after use of the admixtures was presented. The response to mechanical loadings of bent beams made of hydraulically bonded mixture with rubber admixture was considered. The impact of the rubber granulate on the value of fracture energy was analysed. Moreover, the influence of an interfacial transmission zone quality on the achieved effect was assessed. Calculations were conducted by means of the muli-scale numerical model which was built in ABAQUS finite element method environment. The results derived indicate beneficial effect of rubber granulate on fracture energy of hydraulically bonded mixture.
Źródło:
Budownictwo i Architektura; 2017, 16, 3; 95-102
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Odrespiratorowe zapalenie płuc chorych leczonych w oddziale intensywnej terapii
Ventilator-associated pneumonia in patients treated in the intensive care unit
Autorzy:
Kubielas, Grzegorz
Uchmanowicz, Izabella
Powiązania:
https://bibliotekanauki.pl/articles/2119984.pdf
Data publikacji:
2018-09-03
Wydawca:
Europejskie Centrum Kształcenia Podyplomowego
Tematy:
personel pielęgniarski
oddział intensywnej terapii
zakażenia szpitalne
odrespiratorowe zapalenie płuc
wentylacja mechaniczna
toaleta drzewa oskrzelowego
badania mikrobiologiczne
skala niewydolności wielonarządowej APACHE II
nursing staff
intensive care unit
nosocomial infections
ventilator-associated pneumonia
mechanical ventilation
bronchial tree toilet
microbiological examination
multi-organ failure scale APACHE II
Opis:
Wstęp. Pacjent hospitalizowany w oddziale intensywnej terapii (OIT) wymaga ciągłej i wzmożonej opieki realizowanej przez zespół pielęgniarski. Polega ona na zapewnieniu całościowej pielęgnacji, monitorowaniu i wspomaganiu funkcji życiowych, ale także regularnej toalety drzewa oskrzelowego. Jednak nadal obserwowana jest narastająca częstość zakażeń szpitalnych u chorych leczonych w OIT. Jest ona ściśle powiązana z zastosowaniem wysokospecjalistycznych, często inwazyjnych, metod, takich jak wentylacja mechaniczna. Jednym z zakażeń szpitalnych związanych z intubacją tchawicy i mechaniczną wentylacją jest odrespiratorowe zapalenie płuc (VAP). Cel pracy. Ocena porównawcza dwóch metod toalety drzewa oskrzelowego. Celem drugorzędnym jest poprawa jakości opieki pielęgniarskiej u chorych z VAP w OIT na podstawie analizy uzyskanych wyników. Materiał i metody. Badaniami objęto grupę 30 pacjentów Klinicznego Oddziału Anestezjologii i Intensywnej Terapii (KOAIT) 4. Wojskowego Szpitala Klinicznego z Polikliniką we Wrocławiu. Wszyscy chorzy wymagali wentylacji mechanicznej co najmniej 72 godziny z powodu ostrej niewydolności oddechowej. Badaną grupę chorych podzielono ze względu na rodzaj zastosowanej techniki wykonania toalety drzewa oskrzelowego na: grupę I (n = 13) – odsysanie w systemie otwartym oraz grupę II (n = 17) – odsysanie w systemie zamkniętym. U wszystkich chorych pobrano wymaz z drzewa oskrzelowego metodą na ślepo (BBS), a uzyskany materiał przekazywano do laboratorium diagnostyki mikrobiologicznej. Ponadto analizowano dane demograficzne pacjentów oraz stan ogólny w skali APACHE II. Obserwację kończono w momencie zakończenia wentylacji mechanicznej i ekstubacji tchawicy lub z powodu zgonu chorego. Wyniki. Wśród przyczyn niewydolności oddechowej w badanej grupie pacjentów wykazano stan po nagłym zatrzymaniu krążenia (n = 10), uraz wielonarządowy (n = 8), uraz czaszkowo-mózgowy (n = 7) oraz inne (n = 5). Średni czas pobytu w OIT w grupie I wynosił 13 dni, a w grupie II – 11 dni. Liczba badań mikrobiologicznych wykonanych w grupie I wynosiła 70, a w grupie II – 78. Ujemny posiew w grupie I uzyskało 2 z 5 pacjentów do końca badań, a w grupie II było to 4 z 6 pacjentów. Najczęstszym typem drobnoustroju dla grupy I był Staphylococcus aureus dodatni w dobie 0 (n = 4), 3 (n = 4), 6 (n = 4) i 9 (n = 3) oraz Pseudomonas aeruginosa w dobie 12 (n = 2). Z kolei najczęstszym typem drobnoustroju dla grupy II był Acinetobacter baumani dodatni w dobie 0 (n = 5), 3 (n = 5), 6 (n = 5), 9 (n = 3) i 12 (n = 2). Badana grupa chorych nie różniła się istotnie w zakresie danych demograficznych (średni wiek 36 lat w grupie I oraz 42 lata w grupie II; rozkład płci to 9 mężczyzn i 4 kobiety w grupie I oraz 9 mężczyzn i 8 kobiet w grupie II) oraz w wyjściowym stanie klinicznym ocenianym w skali APACHE II (wynik 20 pkt. dla grupy I oraz 21 pkt. dla grupy II). Wnioski. Zastosowanie zamkniętego systemu ssącego pozwala na utrzymanie jałowości dolnych dróg oddechowych przez cały okres (12 dni) leczenia w OIT z użyciem respiratora, a system otwarty zapewnia jałowy posiew jedynie do 6. doby leczenia. Wiedza personelu pielęgniarskiego z zakresu pielęgnacji chorych wentylowanych mechanicznie jest ważnym elementem zapobiegania VAP. Zastosowanie metody pobierania materiału z dolnych dróg oddechowych w codziennej praktyce jest elementem właściwie prowadzonej strategii diagnostyki mikrobiologicznej z zaangażowaniem personelu pielęgniarskiego.
Background. The patient hospitalized in the intensive care unit (ICU) requires continuous and intensified care performed by the nursing team. It consists in providing comprehensive care, monitoring and support of vital functions, as well as a regular toilet in the bronchial tree. However, the increasing incidence of nosocomial infections in patients treated in ICUs is still observed. It is closely related to the use of highly specialized, often invasive methods, such as mechanical ventilation. One of the nosocomial infections associated with tracheal intubation and mechanical ventilation is ventilator-associated pneumonia (VAP). Objectives. The main aim of the study was to compare of the assessment of two methods of the bronchial tree toilet. The secondary aim is to improve the quality of nursing care in patients with VAP in the ICU based on the analysis of the obtained results. Material and methods. The study involved a group of 30 patients of the Clinical Department of Anaesthesiology and Intensive Therapy at the 4th Military Clinical Hospital with the Polyclinic in Wroclaw. All patients required mechanical ventilation for at least 72 hours due to acute respiratory failure. The studied group of patients was divided according to the type of technique used to provide the toilet of the bronchial tree: group I (n = 13) – suction in the open system and group II (n = 17) – suction in a closed system. In all patients a bronchial swab was collected with the blind bronchial sampling (BBS) method and the obtained material was transferred to the microbiological diagnostic laboratory. In addition, patient demographics and the general state of the APACHE II scale were analyzed. Observation was terminated at the end of mechanical ventilation and extubation of the trachea or due to death of the patient. Results. Among the causes of respiratory failure in the examined group of patients, the state after sudden cardiac arrest was found (n = 10), multi-organ trauma (n = 8), craniocerebral trauma (n = 7) and others (n = 5). The average length of ICU stay in group I was 13 days, and in group II – 11 days. The number of microbiological tests performed in group I was 70, and in group II – 78. The negative microbiological test in group I was obtained by 2 out of 5 patients until the end of the study, and in group II it was 4 out of 6 patients. The most common type of microorganism for group I was Staphylococcus aureus positive on the day 0 (n = 4), 3 (n = 4), 6 (n = 4) and 9 (n = 3) and Pseudomonas aeruginosa on the day 12 (n = 2) . In turn, the most common type of microorganism for group II was Acinetobacter baumani positive at 0 (n = 5), 3 (n = 5), 6 (n = 5), 9 (n = 3) and 12 (n = 2). The studied group of patients did not differ significantly in terms of demographic data (mean age 36 years in group I and 42 in group II, sex distribution is 9 men and 4 women in group I and 9 men and 8 women in group II) and in the starting a clinical condition assessed on the APACHE II scale (score 20 points for group I and 21 points for group II). Conclusions. The use of a closed suction system allows the maintenance of sterility of the lower respiratory tract for the entire period (12 days) of ICU treatment with the use of a respirator, and the open system ensures sterile culture only until the 6th day of treatment. The knowledge of nursing staff in the care of mechanically ventilated patients is an important element of VAP prevention. The application of the method of collecting material from the lower respiratory tract in everyday practice is an element of properly conducted strategy of microbiological diagnostics with the involvement of nursing staff.
Źródło:
Współczesne Pielęgniarstwo i Ochrona Zdrowia; 2018, 7, 4; 83-88
2084-4212
Pojawia się w:
Współczesne Pielęgniarstwo i Ochrona Zdrowia
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 24

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