THE APPLICATION OF COMPOSITE MATERIALS IN THE AEROSPACE INDUSTRY

The paper investigates the growing popularity of composite materials concentrating on explanation of their advantages, especially taking into consideration composite materials used in the aerospace industry such as polymer matrix composites, metal matrix composites, ceramic matrix composites and smart composite materials. Various types of matrices and fibers are described with special emphasis on nanotechnology and opportunities to improve the properties of composites. The paper also presents selected examples of applications in the aerospace industry

Modelling and Design of HF RFID Passive Transponders with Additional Energy Harvester

The huge progress in electronics technology and RFID technique gives the opportunity to implement additional features in transponders. It should be noted that either passive or semipassive transponders are supplied with energy that is derived from the electromagnetic field generated by the read/write device and its antenna. This power source is used to conduct radio-communication process and excess energy could be used to power the extra electronic circuits, but the problem is to determine the additional power load impact on the RFID system proper operation and size of interrogation zone. The ability to power the supplementary electronic blocks applied in the HF passive transponders is discussed in detail this paper. The simulation model and test samples with a harvester that recovers energy from the electromagnetic field of read/write device and its antenna have been developed in order to conduct investigations. The harvested energy has been utilized to supply a microprocessor acquisition block for LTCC pressure sensor developed in research previously described by authors

Zakrzepowo-zatorowe nadciśnienie płucne — aktualny stan wiedzy

Przewlekłe zakrzepowo-zatorowe nadciśnienie płucne (CTEPH) stanowi 4. grupę nadciśnienia płucnego według klasyfikacji World Health Organization. Rozwija się zarówno u osób po przebytym incydencie ostrej zatorowości płucnej (PE), jak i u chorych, którzy nigdy nie przebyli jawnego epizodu PE czy zakrzepicy żył głębokich. Nieleczona choroba prowadzi do niewydolności prawokomorowej i zgonu. Choć „złotym standardem” leczenia CTEPH pozostaje endarterektomia płucna (PEA), to ostatnie lata przyniosły znaczący postęp w zakresie rozwoju alternatywnych metod leczenia dla chorych niebędących kandydatami do PEA. Niniejszy artykuł stanowi podsumowanie aktualnego stanu wiedzy na temat patofizjologii oraz leczenia tej jednostki chorobowej

Zakrzepowo-zatorowe nadciśnienie płucne — aktualny stan wiedzy

Chronic thromboembolic pulmonary hypertension (CTEPH) is defined as belonging to group 4 in the World Health Organization classification. It affects both patients after an acute pulmonary embolism (PE) episode and those who have never suffered from a PE or deep vein thrombosis. Left untreated, CTEPH leads to right ventricular failure and death. Though pulmonary endarterectomy (PEA) remains the gold standard in CTEPH treatment, significant progress has been made in recent years in developing alternative treatment methods for patients who are not candidates for PEA. This article sets out current knowledge on CTEPH pathophysiology and treatment methods.Przewlekłe zakrzepowo-zatorowe nadciśnienie płucne (CTEPH) stanowi 4. grupę nadciśnienia płucnego według klasyfikacji World Health Organization. Rozwija się zarówno u osób po przebytym incydencie ostrej zatorowości płucnej (PE), jak i u chorych, którzy nigdy nie przebyli jawnego epizodu PE czy zakrzepicy żył głębokich. Nieleczona choroba prowadzi do niewydolności prawokomorowej i zgonu. Choć „złotym standardem” leczenia CTEPH pozostaje endarterektomia płucna (PEA), to ostatnie lata przyniosły znaczący postęp w zakresie rozwoju alternatywnych metod leczenia dla chorych niebędących kandydatami do PEA. Niniejszy artykuł stanowi podsumowanie aktualnego stanu wiedzy na temat patofizjologii oraz leczenia tej jednostki chorobowej

Administrative Judiciary in Poland in Search for Fairness and Efficiency - an Overview

<p>The 2002 reform of Polish administrative judiciary introduced two – instance system of administrative courts. The main aim of the article is to analyze some of the novelties that are to ensure fairness, cohesion and effectiveness of the administrative judiciary in Poland. First parts of the article are devoted to present in brief the historical and present organization of the administrative judiciary in Poland. In the subsequent parts authors present the problem of cohesiveness of the judicature, mediatory and ‘simplified’ procedures and staffing. Referring to the available data, authors argue that new procedural tools (mediation, simplified procedures) are gradually gaining more acceptance. On the other hand, a lot has to be done to develop ADR means in the pre – trial stage and make them a popular way of administrative dispute resolution.</p

The influence of hydroponic potato plant cultivation on selected properties of starch isolated from its tubers

Starch is a natural polysaccharide for which the technological quality depends on the genetic basis of the plant and the environmental conditions of the cultivation. Growing plants under cover without soil has many advantages for controlling the above-mentioned conditions. The present research focuses on determining the effect of under cover hydroponic potato cultivation on the physicochemical properties of accumulated potato starch (PS). The plants were grown in the hydroponic system, with (greenhouse, GH) and without recirculation nutrient solution (foil tunnel, FT). The reference sample was PS isolated from plants grown in a tunnel in containers filled with mineral soil (SO). The influence of the cultivation method on the elemental composition of the starch molecules was noted. The cultivation method also influenced the protein and amylose content of the PS. Considering the chromatic parameters, PS-GH and PS-FT were brighter and whiter, with a tinge of blue, than PS-SO. PS-SO was also characterized by the largest average diameters of granules, while PS-GH had the lowest crystallinity. PS-SO showed a better resistance to the combined action of elevated temperature and shear force. There was a slight variation in the gelatinization temperature values. Additionally, significant differences for enthalpy and the retrogradation ratio were observed. The cultivation method did not influence the glass transition and melting

Acoustic emission as a valuable technique used for monitoring polymer failures

In the paper, acoustic emission (AE) system was presented as a method that can be used to monitor polymer material failures. Samples fabricated of two aluminum profiles bonded together with a thick layer of cured epoxy resin were subjected to fracture tests. Epidian 53 epoxy resin cured with Z1 curing agent as well as Epidian 5 epoxy resin cured with PAC curing agent were selected as adhesives. Acoustic emission parameters were acquired during Double Cantilever Beam (DCB) tests. The frequencies of elastic waves released during failure were then analyzed using both Fast Fourier Transformation (FFT) and Wavelet Transformation (WT) for the two materials

Experimental Study on Static and Dynamic Fracture Toughness of Cured Epoxy Resins

The paper investigates experimental results of static and dynamic fracture toughness. The three-point bending test and the Charpy pendulum test were performed for two kinds of polymers: Epidian 5 epoxy resin cured with Z1 curing agent and Epidian 53 epoxy resin cured with Z1 curing agent. The comparison between the values of a maximum static and a maximum dynamic force are discussed as well as the values of static and dynamic fracture toughness, with special emphasis on microscopic views of crack propagation

Adaptation of Fracture Mechanics Methods for Quality Assessment of Tungsten Carbide Cutting Inserts

Tungsten carbide (WC) is well known as one of the hardest materials widely used in machining, cutting and drilling, especially for cutting tools production. Knowing fracture toughness grants the opportunity to prevent catastrophic wear of a tool. Moreover, fracture toughness of WC-based materials may vary because of different material compositions, as well as a different way of production. Hence, each material should be treated individually. In this paper, SM25T (HW) tungsten carbide (HW—uncoated grade, TNMR 401060 SM25T, manufactured by Baildonit company, Katowice, Poland) was taken into consideration. Sintered carbides—designated as S—are designed to be applied for machining steel, cast steel and malleable cast iron. Fracture mechanics methods were adapted to make a quality assessment of WC cutting inserts. Both quasi-statical three-point bending tests, as well as Charpy dynamic impact tests, were performed to calculate static and dynamic fracture toughness (KIC and KID, respectively). In addition, a special emphasis was placed on the microscopic analysis of fracture surfaces after impact tests to discuss material irregularities, such as porosity, cracks and so-called “river patterns”. There is a lack of scientific works in this field of study. However, cutting engineers are interested in obtaining the experimental results of that kind. Although there are a few standardized methods that may be used to determine fracture toughness of hard metals, none of them is expected to be the most reliable. Moreover, there is a lack of scientific works in the field of determining static and dynamic fracture toughness of WC by the presented method. The proposed examination solution can be then successfully used to calculate toughness properties of WC-based materials, as the results obtained seem to be with a good agreement with other works