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Tracheobronchomalacia is a rare respiratory disease that is manifesting by impaired ventilation with expiratory collapse of the tracheal wall due to softening of the supporting cartilage and hypotonia of myoelastic elements [1]. Surgery is the mainstay of treatment. We report the case of 39 -year old man with exacerbation of chronic respiratory distress. The membranous wall of the trachea and the large bronchi was stretched to such an extent that the tracheal lumen was almost completely closed during the exhalation phase, and the cartilage bent in the opposite direction taking the opposite C-shape. To plan the operation in detail, we used 3D printing. We made the airway model in 3d using the GE AW-suite software. Then the model was printed on a 3d printer in plastic. The tracheobronchoplasty through right posterolateral thoracotomy was performed. A polipropylen mesh was sewn into the membranous wall of the trachea and main bronchi. A satisfactory wallresult was obtained. 3D printed trachea was very helpful in the planning of the operational strategy.
2020
Robert Dziedzic,
Gustaw Rzyman,
Witold Rzyman
Periodic structures have some interesting properties, of which the most evident is the presence of band gaps in their frequency spectra. Nowadays, modern technology allows to design dedicated structures of specific features. From the literature arises that it is possible to construct active periodic structures of desired dynamic properties. It can be considered that this may extend the scope of application of such structures. Therefore, numerical research on a beam element built of periodically arranged elementary cells, with active piezoelectric elements, has been performed. The control of parameters of this structure enables one for active damping of vibrations in a specific band in the beam spectrum. For this analysis the authors propose numerical models based on the finite element method (FEM) and the spectral finite element methods defined in the frequency domain (FDSFEM) and the time domain (TDSFEM).
2020
Wiktor Waszkowiak,
Marek Krawczuk,
Magdalena Palacz
The numerical modelling of structural elements is an important aspect of modern diagnostic systems. However, the process of numerical implementation requires advanced levels of consideration of multiple aspects. Important issues of that process are the positive and negative aspects of solution applied methods. Therefore the aim of this article is to familiarise the reader with the most important aspects related to the process of numerical modelling of one-dimensional problems related to the phenomena of the propagation of elastic waves and their application for damage detection purposes.
2020
Magdalena Palacz,
Arkadiusz Żak,
Marek Krawczuk
This article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under various operating conditions, and an algorithm for selecting the parameters of a third-order C-type filter (for suppressing the second harmonic) and two second-order LC-type filters (for suppressing the third harmonic) was proposed. The filtering system was tested in an arc furnace with the highest rated power, and harmonics in the current spectrum were evaluated. The results of the measurements were used to analyze the effectiveness of the compensation system comprising two passive C-type and LC-type filters at different system configurations. C-type filters significantly influenced current harmonics. The influence of the changes in the number of arc furnace transformers on the true Root Mean Square (RMS) of the currents injected into the 110 kV transmission system and on the voltages of the 110 kV busbars was discussed.
2020
Andrzej, Grzegorz Lange,
Grzegorz Redlarski
Background: The purpose of this study was to analyze hemodynamic changes in patients treated with percutaneous coronary intervention (PCI) at an early stage of acute myocardial infarction (AMI) and at one-month follow-up. Methods: Patients with AMI (n = 27) who underwent PCI were analyzed using impedance cardiography (ICG). ICG data were collected continuously (beat by beat) during the whole PCI procedure and thereafter at every 60 s for the next 24 h. Blood pressure was taken every 10 min and stored for analysis. Additionally the following parameters were measured: cardiac index (CI), stroke volume index (SVi), left cardiac work index (LCWi), contractility index (CTi), ventricular ejection time (VET), systemic vascular resistance index (SVRi), thoracic fluid content index (TFCi) and heart rate (HR). Results: In the first 24 h after PCI all the contractility parameters including CI, SVi, LCWi, CTi and VET significantly decreased, whereas HR, SVRi and TFCi increased compared to baseline. All of the parameters examined got normalized at one month. The CI, SVi, LCWi, CTi, SVRi did not significantly differ from baseline, however the HR and VET were significantly lower compared to first day after PCI. Conclusions: 1. Cardiac performance deteriorates early after PCI and normalizes after one month in patients with an AMI. 2. ICG is useful for hemodynamic monitoring of AMI patients during and after invasive therapy.
2020
Łukasz Lewicki,
Maria Fijałkowska,
Maciej Karwowski,
Konrad Siebert,
Grzegorz Redlarski,
Aleksander Pałkowski,
Radosław Targoński,
Janusz Siebert
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