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EN
The paper shows a preliminary study of the basic strength parameters of printed parts made of biocompatible polymers with ceramic layers applied to increase the strength of the tool cutting surface. Methods: The specimens were made from different materials and using different 3D printing technologies and the working surfaces that will eventually form the cutting element of the tool were coated with Al2O3. Gloss tests were conducted, properties of the coating, a scratch test of the coated surface, also evaluated surface topography. Results: Based on the conducted research, it was found that polymeric materials are characterized by sufficient strength and can be used for disposable tools, however, the use of thin layers of Al2O3 significantly increases the surface strength parameters, which may have a significant impact on the reliability and durability of the tools. The polymer surface covered with an Al2O3 layer is characterised by increased scratch resistance ranging from 24% to 75% depending on the core material and printing technology. The gloss of the surfaces is disproportionately low compared to currently used metal tools, which indicates that they can be used in endoscopic procedures. Conclusions: Based on the conducted research, it was found that the use of thin layers of Al2O3 covering polymer 3D prints is an excellent way to increase strength parameters such as scratch resistance, tribological parameters and light reflections arising on the surface as a result of endoscopic lighting are disproportionately small compared to metallic biomaterials. This gives great hope for using polymer 3D prints for personalised neurosurgical tools.
EN
Despite significant advances in diagnosis and treatment, cardiovascular disease remains a major cause of premature death. Approximately 80% of cardiovascular incidents can be prevented by optimizing risk factor control and lifestyle modification, including dietary change. Treatment of cardiovascular disease, like treatment of other diseases, can be divided into conservative and curative. Conservative treatment is based on pharmacotherapy, while surgical treatment is mainly based on the use of PCI (percutaneous coronary intervention) procedures, i.e., increasing blood flow through narrowed arteries. This effect can be achieved with stents. The main limitation of metal stents is their permanent presence within the body, which can lead to complications such as thrombosis. A more advanced solution is the use of polymer or drug-coated stents, both of which are made of biodegradable materials. These stents are designed to release medications to support treatment and maintain their shape within the blood vessel before being naturally absorbed and eliminated by the body. In this study, the surface of stents made of polylactide was modified by applying a layer of PLGA using an ultrasound method. The study was carried out for uncoated and coated stents in both the initial state and after exposure to artificial plasma flow. The scope of the work included microscopic observations, weight measurements of the specimen, and examination of radial forces. The analysis of the results showed no clear effect of exposure on stent weight, but a clear effect of long- -term exposure on radial forces was observed.
EN
The main aim of the researches was the three-dimensional morphological assessment of the mandible in children. Materials&Methods: The research group consisted of 34 infants from 21 to 417 days of age (0-13 months). Models of the mandibles were developed on the basis of tomographic images. Characteristic anatomical points were marked on the models, on the basis of which characteristic distances and angles were calculated, determining the length, width and height of the mandible as well as its proportion and symmetry. Based on the obtained database, models of mandibular growth in the first year of life in three directions were also developed. Conclusion: The analysis of the results revealed some significant objective information on the growth and development of the normal mandible.
EN
The desire to increase the comfort of patients and to continue production despite the decreasing amount of available materials on the market has led to the constant search for novel materials that could be used to obtain tracheobronchial tubes. The aim of this study is to determine the mechanical properties of a new thermoplastic elastomer. Two materials - the thermoplastic elastomer and the natural rubber were subjected to three tests: static tensile test, static compression test and static three-point bending test. During the static tensile test, samples of the tested materials were examined, and during the next two examinations, the final products. The materials underwent the processes of sterilization, hydrolytic degradation and degradation by oxidation. The treated samples were also tested in order to compare the obtained results. The mechanical properties of the tested materials improved both after the hydrolytic degradation and oxidative degradation, as well as after the sterilization process. Yet the thermoplastic elastomer revealed a more noticeable increase. The elastomer hardening is a positive phenomenon potentially leading to fewer accidental closures of the tubes cross-section. Both the sterilization process and various degradation methods improved the mechanical properties by strengthening the tested materials. This phenomenon seems to be desirable to avoid the closure of the implemented tube during its application.
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EN
Road traffic accidents involving coaches do not happen very often, but they are very dangerous because they affect a large number of passengers. Coaches (or intercity buses) are not equipped with safety belt harnesses. Valid regulations do not impose any obligation on coach manufacturers to provide intercity buses with either two- or three-point safety belts. This fact may result from the unawareness of risks and injuries that might befall the passengers with no safety belts during accidents. That is the reason why this work aims to compare the aftermath of coach accidents with no safety belts and the ones with safety belts. A detailed aim of this research is to analyse the results of dynamic loads during a frontal impact exerted on coach passengers travelling with and without (two- and three-point) safety belts. This objective was achieved by performing experimental studies and modelling which focused on the process of dynamic load transfer on the human body during a traffic accident. The research was conducted parallel on an adult and a child. The equivalent of a 50th percentile male was a hybrid III dummy (M50), whereas a child at the age of about 10 was represented by a P10 dummy. A numerical model was generated and verified in experimental testing in the scope of kinematics. Also, the comparison of the recorded courses of forces, acceleration, and moments was conducted. The results obtained from the tests were analyzed regarding the injury criteria for head, neck, and thorax. It was observed that both for the two-point safety system and the lack of safety belts, there were high values of acceleration recorded in the centre of gravity of the head. On the basis of the investigations conducted, it was ascertained that only a three-point safety belt system ensures the satisfaction of all injury criteria within admissible standards both in the case of criteria defined in the rules no. 80 and the rules no. 94 determined by the United Nations Economic Commission for Europe. It is the three-point safety belt system which should be obligatory in all intercity buses.
PL
Celem przeprowadzonych badań była ocena obciążeń występujących w odcinku lędźwiowym kręgosłupa człowieka na poziomie L4-L5 dla schorzenia kręgozmyku. Modele numeryczne poszczególnych części segmentu ruchowego zostały wysegmentowane w oparciu o zdjęcia tomografii komputerowej. Następnie w oprogramowaniu MES przeprowadzono analizę numeryczną modelu kręgosłupa fizjologicznie prawidłowego oraz modeli z różnymi stopniami kręgozmyku w następującej skali: 4 mm, 6 mm, 8 mm, 10 mm oraz 12 mm.
EN
The research carried out a numerical analysis of the loads occurring in the lumbar spine at the L4-L5 level. The project started with modeling the spine diseases in the Inventor 2018 software for different values of spondylolisthesis. In ANSYS Workbench 2013, numerical simulations were performed: analysis of a physiologically correct model, analysis of the mathematical model of the spine with various degrees of spondylolisthesis (4 mm, 6 mm, 8 mm, 10 mm and 12 mm). Models were verified on the basis of literature data.
EN
Purpose: The aim of this paper was the development of a finite element model of the soldier’s head to assess injuries suffered by soldiers during blast under a light armoured vehicle. Methods: The application of a multibody wheeled armoured vehicle model, including the crew and their equipment, aenabled the researchers to analyse the most dangerous scenarios of the head injury. These scenarios have been selected for a detailed analysis using the finite element head model which allowed for the examination of dynamic effects on individual head structures. In this paper, the authors described stages of the development of the anatomical finite element head model. Results: The results of the simulations made it possible to assess parameters determining the head injury of the soldier during the IED explosion. The developed model allows the determination of the parameters of stress, strain and pressure acting on the structures of the human head. Conclusion: In future studies, the model will be used to carry out simulations which will improve the construction of the headgear in order to minimize the possibility of the head injury.
PL
W pracy przedstawiono wyniki badań wytrzymałościowych materiału wykorzystywanego do produkcji rurek tracheostomijnych oraz dwóch materiałów, przewidzianych do ich produkcji w nowej technologii wywarzania. Przebadano trzy materiały (polietylen małej gęstości przeznaczonego do wytłaczania - polietylen nr 2 oraz dwóch polietylenów małej gęstości przeznaczonych do przetwarzania za pomocą procesu wtrysku - polietylen nr 1 oraz polietylen nr 3) dla których wyznaczono maksymalną siłę zginającą i ściskającą oraz maksymalne naprężenia. Uzyskane wyniki badań poddano analizie w celu poszukiwania optymalnego materiału wykorzystywanego w procesie produkcyjnym.
EN
The paper presents the results of strength tests of the material used for the production of tracheostomy tubes and two materials intended for their production in the new manufacturing technology. Three materials (low density polyethylene intended for extrusion - polyethylene No. 2 and two low density polyethylenes intended for injection molding - polyethylene No. 1 and polyethylene No. 3) were tested for which the maximum bending and compressive force and maximum stress were determined. The obtained test results were analyzed in order to search for the optimal material used in the production process.
EN
The aim of this paper was to evaluate which method of acellularization and sterilization is optimal, in the meaning of which processes have the least impact on the deterioration of mechanical properties of porcine tissues used for xenogeneic applications. Methods: The static tensile probe was conducted for 80 skin specimens obtained from transgenic swine, which are used as a wound dressing for skin recipient. Obtained data were subsequently analyzed with the use of statistical methods. Results: It was found that Young’s modulus for the samples after the sterilization process for the dispase substance and the mixed method (SDS + trypsin) were statistically significantly changed. In the case of dispase, Young’s modulus value before the sterilization process was 12.4 MPa and after the value increased to 28.0 MPa. For the mixed method (SDS + trypsin) before the sterilization process Young’s modulus value was 5.6 MPa and after it was increased to 6.3 MPa. The mixed method (SDS + trypsin) had the slightest effect on changing the mechanical properties of the samples before and after the sterilization process. Conclusions: It was confirmed that different methods of acellularization and the process of sterilization have an influence on the change of mechanical properties of the skin of transgenic swine. In the authors’ opinion, the mixed method (SDS + trypsin) should be recommended as the best one for the preparation of transgenic porcine dermal dressings because it ensures a smaller probability of dressing’s damage during a surgical procedure.
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