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EN
Fragments of research to formulate criteria allowing for the rational design of covers to protect against the destructive impact effects of small, sharp elements, are discussed. The motivation for this research was the result of the analysis of damage to composite covers which protect the chassis of a modern traction vehicle, moving at high speed on Polish railway routes. Such covers must have appropriate strength properties and high surface resistance to external damage, while limiting the influence of the impact of foreign elements on the cover, and the impact of external sources of noise and vibrations on the interior of the vehicle. They have a sandwich structure and are made of a polymer composite. General guidelines for the design of covers having the required properties are not known. A method of analyzing the resistance of the cover to damage associated with the impact of elements with sharp edges and irregular shapes, using the LS-Dyna software, has been proposed. For the needs of the proposed method, a general model of the cover structure has been introduced. The assumptions adopted in determining the field of possible solutions are discussed. Particular attention is paid to the required structure of the cover, allowing for the differentiation of its properties observed in the longitudinal and transverse directions of the vehicle. Selected conclusions resulting from the research carried out so far, are presented.
EN
This paper presents research regarding refill friction stir spot welding (RFSSW) of EN AW-7075-T6 Alclad aluminium alloy sheets, and the joint behaviour under static and dynamic loads. Single-point lap joint of sheets with different thicknesses, which corresponds to those used in aircraft fuselage structures, i.e. upper sheets with a thickness of 1.6 mm and lower sheets with a thickness of 0.8 mm, were analysed regarding the failure mechanism in static shear testing. It has been shown that a properly made joint is destroyed as a result of tension in the lower plate. The lower plate at the edge of the weld is structurally weakened by the HAZ, but also geometrically due to plastic deformation during the welding process, which has been demonstrated by metallographic investigations as well as by the FEM numerical model. Single-row RFSSW welded joints with different spacing of the welds and a riveted joint were impact tested. It has been shown that welded joints are characterized by a greater stiffness, which is higher when the spacing of the welds is smaller.
PL
Praca przedstawia badania połączenia zakładkowego RFSSW blach ze stopu aluminium EN AW-7075-T6 Alclad pod wpływem obciążeń statycznych oraz dynamicznych. Jednopunktowe połączenie zakładkowe blach o różnej grubości co odpowiada połączeniom stosowanym w konstrukcjach kadłubów lotniczych tj. górna blacha o grubości 1.6 mm oraz dolna blacha o grubości 0.8 mm, poddano analizie mechanizmu zniszczenia w próbie statycznego ścinania. Wykazano, że poprawnie wykonane połączenie ulega zniszczeniu na skutek rozciągania dolnej blachy. Dolna blacha przy krawędzi zgrzeiny jest osłabiona strukturalnie przez strefę wpływu ciepła, ale także geometrycznie poprzez deformację plastyczną powstałą podczas procesu zgrzewania, co wykazano na podstawie badań metalograficznych jak również przy użyciu modelu numerycznego MES. Jednorzędowe połączenia zakładkowe poddano badaniom udarności. Badano połączenia zgrzewane RFSSW o różnym rozstawie zgrzein oraz połączenie nitowane. Wykazano, że połączenia zgrzewane charakteryzują się większą sztywnością, która jest tym większa im mniejszy rozstaw zgrzein.
EN
Ultra-high molecular weight polyethylene (UHMWPE) is one of important materials utilized against impacting threats. In this work, bulk UHMWPE specimens were fabricated in a compression molding chamber, and molding parameters such as pressure and temperature were varied in the specimen preparation stage to investigate the effect of molding parameters on the impact performance. In addition, silicon carbide fillers were included in the UHMWPE matrix to enhance the anti-impact properties of the specimens. From the results, high molding pressure provides enhanced impact resistance due to improved microstructural consolidation. On the other hand, molding temperature just above the melting point of polymer is much beneficial to the anti-impact behavior of the structures. Carbide fillers lead to an increase in the frictional interaction between the impactor and composites and thereby enhancing the impact resistance of the structures. However, the gain in the protective properties performance is restricted up to a certain amount of carbide loading because at higher filler ratios, the composites change from ductile to brittle characteristics. For this reason, crack growth susceptibility develops in the composites at excessive carbide loadings.
EN
The paper presents the results of the compression tests for carbon-epoxy composites in order to assess the amount of energy absorbed depending on the process velocity and content of axial fibres. Two types of prepreg (UD 200 g/m2 and woven 160 g/m2) were used to prepare the specimens with a diameter of 20 mm and a height of 34 mm. The specimens were subjected to compression under various speed conditions (static, dynamic and SHPB tests). The calculated specific energy absorption values showed a 50–60% decrease with increasing process velocity and depending on the type of specimens architecture. The highest energy values were absorbed by the specimens with the highest share of axial fibres in the sample.
EN
The aim of the study was to compare the physical and mechanical properties of known prostheses for cranioplasty: knitted Codubix based on polypropylene and Modela-cryl resin based on PMMA. It was expected that the study would allow to check whether it is possible to combine their properties, which should enable the preparation of a new material with properties combining the best features of both components. Physico-chemical and mechanical properties were evaluated. It was found that the two materials meet the requirements for chemical purity, ensuring the safety of their use. Regarding the mechanical properties, the energy of impact diffusion for two types of prostheses was determined applying the Drop Tower technique. The polymerisation heat of Modela-cryl resin was determined in real time using the DSC technique.
PL
Celem pracy było porównanie właściwości fizycznych i mechanicznych znanych protez do kranioplastyki: dzianej Codubix na bazie polipropylenu i żywicy Modela-cryl na bazie PMMA. Oczekiwano, że badanie pozwoli sprawdzić, czy możliwe jest połączenie ich właściwości, co powinno pozwolić na przygotowanie nowego materiału o właściwościach łączących najlepsze cechy obu komponentów. Oceniono właściwości fizykochemiczne i mechaniczne. Stwierdzono, że oba materiały spełniają wymagania czystości chemicznej, zapewniając bezpieczeństwo ich stosowania. Jeśli chodzi o właściwości mechaniczne, określono energię dyfuzji uderzeniowej dla dwóch typów protez przy użyciu techniki Drop Tower. Określono ciepło polimeryzacji żywicy Modela-cryl w czasie rzeczywistym za pomocą techniki DSC.
EN
In the knock-out process, as well as in the preliminary phase of moulding sand reclamation, the issue of energy demand for the process of crushing used sand agglutinations, preferably to single grains, is particularly important. At present, numerical values of moulding sand impact resistance, which would allow energy-related aspects of this process to be forecast, are not known, as such research has not been carried out. It seems that impact resistance tested on very small cross-section samples, which allows us to very precisely reveal some unique features of a moulding sand with organic and inorganic binders, is an important parameter, which so far has not been taken into account for evaluation of mechanical properties of moulding sands. Preliminary attempts to determine impact resistance of moulding sands have been carried out as part of own research of the author. The conducted investigations aimed at determining the relationships between the obtained values of tensile strength and impact resistance of moulding sands. In addition, the effect of holding samples at temperatures of 100oC, 200oC, 300oC on the value of impact resistance was determined, both for sands made with fresh and with reclaimed sand grains.
EN
The paper describes influence of rare earth metals (REMs) on G20Mn5 cast steel microstructure and mechanical properties. The cerium mixture of the following composition was used to modify cast steel: 49.8% Ce, 21.8% La, 17.1% Nd, 5,5% Pr and 5.35% of REMs. Cast steel was melted in industrial conditions. Two melts of non-modified and modified cast steel were made. Test ingots were subject to heat treatment by hardening (920°C/water) and tempering (720°C/air). Heat treatment processes were also performed in industrial conditions. After cutting flashes off samples of cast steel were collected with purpose to analyze chemical composition, a tensile test and impact toughness tests were conducted and microstructure was subject to observations. Modification with use of mischmetal did not cause significant changes in cast steel tensile strength and yield strength, while higher values were detected for fractures in the Charpy impact test, as they were twice as high as values for the data included in the PN-EN 10213:2008 standard. Observations performed by means of light and scanning microscopy proved occurrence of significant differences in grain dimensions and morphology of non-metallic inclusions. Adding REMs resulted in grain fragmentation and transformed inclusion shapes to rounded ones. Chemical composition analyses indicated that round inclusions in modified cast steel were generally oxysulphides containing cerium and lanthanum. In the paper the author proved positive influence of modification on G20Mn5 cast steel mechanical properties.
EN
The present work, presented the study of effect of different inoculants on impact toughness in High Chromium Cast Iron. The molds were pouring in industrial conditions and samples were tested in laboratory in Faculty of Foundry Engineering at AGH. Seven samples were tested - one reference sample, three with different addition of Fe-Ti, and three with different addition of Al. The samples were subjected to impact toughness on Charpy hammer and the hardness test. The presented investigations indicate that for the each inoculant there is an optimal addition at which the sample obtained the highest value of impact toughness. For the Fe-Ti it is 0.66% and for Al is 0.17%. Of all the examined inoculants best results were obtained at a dose of 0.66% Fe-Ti. Titanium is a well-known as a good modifier but very interesting results gives the aluminum. Comparing the results obtained for the Fe-Ti and Al can be seen that in the case of aluminum hardness is more stable. The hardness of all samples is around 40-45 HRC, which is not high for this type of cast iron. Therefore, in future studies it is planned to carry out the heat treatment procedure that may improves hardness.
PL
W artykule zaprezentowano wyniki udarności powłok kompozytowych na osnowie termoplastycznej z różną liczbą warstw z tkanin aramidowych. Wzmocnione tkaniną aramidową o gramaturze 175 g/m2 powłoki z kopolimeru styren-butadien-styren na podłożu stalowym były otrzymane metodą prasowania. Otrzymano również powłoki bez wzmocnienia o różnej grubości. Wynikiem odporności na uderzenia była ilość uderzeń potrzebnych do mechanicznego uszkodzenia powłoki oraz pęknięcia podłoża. Analizie mikroskopowej poddano również powierzchnie powłok po jednokrotnym uderzeniu. W wyniku przeprowadzonych badań nie zaobserwowano liniowej zależności pomiędzy grubością powłok, a ich odpornością na uderzenia. Znaczący wpływ na powstałe uszkodzenia po udarze ma ilość tkanin w powłoce.
EN
The article presents the results of impact composite coatings on the thermoplastic matrix with varying amounts of aramid fabrics. To prepare composite coatings applied thermoplastic copolymer of SBS (styrenebutadiene- styrene) with a linear chain, trade name Kraton. To reinforcement selected aramid fabric (Twaron 1210 fiber), a plain weave and a weight of 175 g / m2. As the base polymer coatings used steel sheet with a thickness of 1.0 mm marked with DC01 according to EN 10027-1: 2007. It is a quality steel alloy designed for cold-rolled products. Steel substrate were washed in a solution of water and detergent, and then degreased with acetone. First step was compressed at 180 ° C for 3 minutes without load, and then three minutes with a load of 2 MPa. SBS copolymer film having a thickness of 800 μm. The films again were compressed with fabrics on steel substrate, using the same compression parameters as in the case of a single film. Obtained four reinforced with fabric layers differing in number of layers of fabric and two SBS copolymer coating with different thickness. Impact resistance test consisted of placing the sample of 100 x 100 mm in the base device, and then leaving from the height of 1 meter, a weight of 2 kg terminated spherical indenter having a diameter of 20 mm. All samples from a single impact energy of 19.62 J were subjected to microscopic analysis. The first step was to determine the number of impact, after which the steel substrate coating has been without a break. Then carried out research on coatings by measuring the amount of impact, which was interrupted after the structure of the coating and the steel substrate. As a result of the study, there was no linear relationship between the thickness of coatings and their impact resistance. A significant influence on the resulting damage after an impact is the amount of fabric coating.
EN
Growing market demand, more and more efficient and cleaner vehicles create a challenge for automotive industry. Properties of aluminum, such as: high strength stiffness to weight ratio, high fluidity and castability, easy machinability and weldability and good corrosion resistance make them ideal candidate to replacement of a heavier materials used in vehicles, and the same, have direct effect on fuel consumption. Comparing to steel, titanium or carbon fibers, aluminum alloys are characterized by low impact strength, which can be improved by a heat treatment. In this study one investigated the effect of the heat treatment (natural ageing) on the EN AC-AlSi9Cu3(Fe) alloy modified with strontium. Solution heat treatment temperature’s ranges were selected on the base of heating (melting) curves recorded with use of the thermal derivative analysis (ATD) method. Temperatures of the solution heat treatment were 495°C, 510°C, and 525°C ± 5°C, while the solutioning time ranged from 15 to 105 minutes (15; 60 and 105 min.). Time of the ageing amounted to 1, 3 and 7 days. To determine impact strength of the alloy after performed heat treatment one implemented simplified Charpy test. Maximal values of the impact strength (9,6 J/cm2) were obtained for solutioning temperature 510°C and solutioning time 15 minutes, after seven days of ageing. Obtained results enabled determination of solutioning parameters, which allow obtainment of increased impact strength of the investigation alloy for the T4 heat treatment.
PL
Powszechnie stosowane na osłony, zderzaki, obudowy maszyn i urządzeń laminaty poliestrowo-szklane z racji pełnionej funkcji są narażone na różnego rodzaju dynamiczne oddziaływanie siły skupionej. Uderzenia często mają charakter powtarzających się cyklicznie zdarzeń. W artykule zaprezentowano wyniki badań dotyczące laminatów poliestrowo-szklanych wzmocnionych matami oraz tkaninami poddanych kilkudziesięciokrotnym uderzeniom. Zastosowano znormalizowaną metodę spadającego grota, metodę stopniowego wyznaczania. Wyniki pomiarów wskazują na dużą odporność na przebicie laminatów wykonanych z tkanin szklanych, równocześnie wskazują na znalezienie rozsądnego kompromisu pomiędzy laminatami o znacznej sztywności, tańszych, wykonanych z mat, a dużą wytrzymałością na uderzenia laminatów o stosunkowo niskiej sztywności przy małej liczbie warstw tkanin, przez to tańszych.
EN
Commonly used on the cover, bumpers, machinery and equipment enclosures polyester-glass laminates because of their function are exposed to various types of dynamic interaction of concentrated force. Strokes often are cyclically repeated events. The article presents the results of research on fi berglass reinforced mats and textiles of glass fi ber treated multiple repeated impacts. Used a standardized method of falling the mainsail, progressive method of selection. The measurement results indicate a high resistance to puncture laminates made from glass fabric, while point to fi nd a reasonable compromise between the laminates of substantial the stiffness, cheaper, made of a mat, and the high impact resistance of laminates with relatively low the stiffness at low number of layers of fabrics.
EN
Studies described in this paper relate to common grades of cast corrosion resistant Cr-Ni steel with different matrix. The test materials were subjected to heat treatment, which consisted in the solution annealing at 1060°C followed by cooling in water. The conducted investigations, besides the microstructural characteristics of selected cast steel grades, included the evaluation of hardness, toughness (at a temperature of -40 and +20°C) and type of fracture obtained after breaking the specimens on a Charpy impact testing machine. Based on the results of the measured volume fraction of ferrite, it has been found that the content of this phase in cast austenitic steel is 1.9%, while in the two-phase ferritic-austenitic grades it ranges from 50 to 58%. It has been demonstrated that within the scope of conducted studies, the cast steel of an austenitic structure is characterised by higher impact strength than the two-phase ferritic-austenitic (F-A) grade. The changing appearance of the fractures of the specimens reflected the impact strength values obtained in the tested materials. Fractures of the cast austenitic Cr-Ni steel obtained in these studies were of a ductile character, while fractures of the cast ferritic-austenitic grade were mostly of a mixed character with the predominance of brittle phase and well visible cleavage planes.
PL
Zaprezentowane w artykule badania dotyczą popularnych gatunków kwasoodpornego staliwa Cr-Ni o różnej osnowie. Zastosowane do badań materiały poddano obróbce cieplnej (przesycanie w temperaturze 1060°C i chłodzenie w wodzie). Przeprowadzone badania oprócz charakterystyki mikrostruktury wybranych gatunków staliwa obejmowały ocenę twardości, udarności (w temperaturze -40 i +20°C) oraz charakteru przełomów uzyskanych w wyniku złamania próbek na młocie Charpie'go. Na podstawie uzyskanych wyników udziału objętościowego ferrytu stwierdzono, że w staliwie austenitycznym występuje 1.9% tej fazy, natomiast w dwóch staliwach ferrytyczno-austenitycznych (F-A) udział ferrytu mieścił się w przedziale 50÷58%. Wykazano, że staliwo o strukturze austenitycznej charakteryzuje się wyższą udarnością w porównaniu do dwufazowego staliwa ferrytyczno-austenitycznego (F-A). Zmiany jakie zaszły w charakterze przełomów próbek były odzwierciedleniem uzyskanych wyników udarności badanych materiałów. W zakresie przeprowadzonych badań przełomy austenitycznego staliwa Cr-Ni wykazują charakter ciągliwo-kruchy, a przełomy staliwa F-A są przeważnie przełomami o charakterze mieszanym z przewagą przełomu kruchego z widocznymi płaszczyznami łupliwości.
EN
Magnesium alloys play an important role in the development of light metal matrix composites. Magnesium based metal matrix composites reinforced by particles and fibres (especially carbon fibres) are successfully applied in various fields of automotive and aircraft industry. Equally high potential in large-batch production regarding to relatively low price and high strength is expected from MMC with wires made of iron-based alloys. However, their application is hampered by the absence of intermetallic phase between iron and magnesium and low solubility of iron in magnesium. This paper makes a contribution to the investigation of the effect of steel wires surface preparation and of optimised production methods to improve the quality and type of adhesion with selected industrial magnesium alloys. The Fe/Mg-MMC specimens with steel wires reinforcement were manufactured by the help of advanced gas pressure infiltration method (GPI) in a graphite mould at Institute of Lightweight Engineering and Polymer Technology (ILK) of TU Dresden. For the examination of the obtained composites the computer tomography (CT), SEM microscopy with EDX, strength tests and fracture surface inspection has been used.
EN
More and more stringent requirements concerning mechanical and technological properties, which are imposed on materials used to castings of heavy duty machinery components extort implementation of modern selection methods of alloying additives (synthesis of alloys), modifying agents and heat treatment. Obtainment of optimal results, i.e. improvement of mechanical properties of processed alloy as well as its economic aspect are connected with selection of a suitable temperatures and durations of solution heat treatment and ageing operations. In the paper is present an effect of modification and heat treatment processes on KCV impact strength of the EN AC-46000 alloy. Investigated alloy underwent typical treatments of refining and modification, and next heat treatment. Temperatures’ range for heat treatment operations was evaluated with used of the ATD method. Obtained results concern registered curves of melting and solidification with use of the ATD method and the impact strength. On base of performed tests one has determined a range of heat treatment parameters which create conditions to suitable impact strength of the EN AC-46000 alloy.
15
Content available remote Influence of gradual austenitizing on chosen properties of ADI
EN
Ferritic ductile cast iron was quench-hardened with the isothermal transformation in the range of temperatures 400÷300 °C, in the range of time 7,5÷240 min. Soaking before the transformation was gradual. Nominal austenitizing temperature t = 950 °C, and then there appeared cooling to t[gamma] = 850 or 800 °C. Heat treatment was performed with the usage of specimens for the impact strength test, and after that hardness was measured and microstructure analyzed. Test results were used to elaborate mathematical equations and to make threedimensional charts with the usage of STATISTICA and EXCEL software. It was stated, that austenitizing temperature and conditions of the isothermal transformation influence on hardness and impact strength of ADI. On the base of hardness and impact strength it can be stated that as a result of gradual austenitizing of specimens there was obtained ADI corresponding to grades of ASTM 897 (850/550/10) Grade 1, (1050/700/7) Grade 2 and (1200/850/4) Grade 3.
EN
Austenitizing during quench hardening of the ductile cast iron influences the content of carbon in austenite depending on the soaking heat. On the other hand, the saturation of austenite impacts its transformation in the ausferritizing process of a metal matrix and forming of microstructure. Ductile cast iron with the ferrite matrix was hardened with isothermal transformation in the range of ausferritizing in temperature [...]. Microstructure was investigated, there were also defined the proportion of austenite in the matrix of the cast iron and the content of carbon in it and hardness and impact strength in unnotched specimens. It was stated, that the precooling temperature deciding on the content of carbon in austenite influences kinetics of the ausferritic transformation, the content of carbon in the [gamma] phase and impact strength and, in a less degree, hardness. As a result of gradual austenitizing the cast iron after quench hardening, in some conditions of treatment, reached mechanical properties corresponding, according to the ASTM A 897 standard, with high grades of ADI. Chilling in the range of austenitizing in temperature 850 and 800 oC led to the decrease of carbon in austenite what influenced positively on the matrix microstructure and properties of the ADI. Investigations in this range will be continued.
PL
W pracy przedstawiono wyniki badań strukturalnych oraz badań udarności żeliwa sferoidalnego austenitycznego z różnymi dodatkami niklu (15% do 30%) oraz manganu ok. 1.6%. W miarę zwiększania zawartości Ni pojawiają się obok grafitu kulkowego, zdegenerowane wydzielenia grafitu (grafit „chunky”). Wprowadzenie manganu do żeliwa wysokoniklowego powoduje zanik wydzieleń martenzytu w osnowie oraz wyraźne zwiększenie udarności w niskich temperaturach. W pracy przedstawiono omówienie wyników i wnioski.
EN
The study shows the results of impact strength tests carried out on austenitic ductile iron with various additions of nickel (15%÷30%Ni) and 1.6% manganese. By increasing the Ni content it was obtain ductile iron with degeneration of graphite nodules and so called “chunky” graphite. Introducing into liquid cast iron the amount of Mn approximate adequately 1,6% cause the austenitic matrix is observed in nodular cast iron and increasing impact strength. The final part of the study includes discussion of results and conclusions.
PL
Praca dotyczy badań modelowych osłon wykonanych z tworzyw sztucznych pod kątem ich odporności na uderzenia impulsowe z wykorzystaniem metody elementów skończonych. Badaniom poddana została osłona o strukturze przekładkowej składająca się z dwóch zewnętrznych warstw wykonanych z laminatu z włókien węglowych połączonych z rdzeniem wykonanym z pianki poliuretanowej. Wyniki tych symulacji pozwoliły na uzyskanie odpowiedzi przy jakich prędkościach zderzenia dojdzie do perforacji osłony, co związane jest z całkowitym jej zniszczeniem. Dzięki symulacjom stało się również możliwe ustalenie przebiegu procesu zderzenia i znalezienie słabych punktów osłon.
EN
This work concerns investigations of shield model made from composite materials from the point of view of resistance onto impact hitting with utilization finite element method. Investigations was surrendered on sandwitch structure shield made from two external layers from carbon fibre laminate join with polyurethane foam core. Results of this simulation permitted onto obtainment of answer at what speeds of crash it will perforated, what is connected with total destruction. Thanks to simulation was possible settlement of course of destruction process and finding of weak points of shield.
EN
As a part of a broader study of new laminates for marine structures a drop weight impact response and residual compression strength after impact of four laminates reinforced with carbon, carbon and glass, Kevlar/carbon and Kevlar/glass fabrics have been studied. Impact damage surface area corresponding to the impact energy level has been estimated by means of air-coupled ultrasonic C-scan technique. Minor differences in performance of laminates in which carbon fibres have been partly replaced by glass fibres may indicate that carbon fibre laminates can be replaced by cheaper carbon/glass or Kevlar glass laminates.
PL
W ramach szerszego programu badań zastosowania nowych materiałów na konstrukcje okrętowe zbadano odporność na uderzenia spadającym ciężarem i poudarową wytrzymałość na ściskanie czterech laminatów wzmocnionych włóknem: węglowym, węglowym i szklanym, Kevlarowym/węglowym, Kevlarowym/szklanym w postaci tkanin. Rozmiar strefy zniszczeń odpowiadających danemu poziomowi energii uderzenia, przyjęty jako kryterium odporności udarowej został wyznaczony metodą ultradźwiękową ze sprzężeniem powietrznym. Niewielkie różnice w zachowaniu materiałów uzyskane dla laminatów, w których włókna węglowe zastąpiono częściowo szklanymi wskazują na możliwość zastępowania laminatów wzmocnionych włóknami węglowymi tańszymi laminatami węglowo-szklanymi lub Kevlarowo/szklanymi.
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