Wyniki wyszukiwania - Biblioteka Nauki

1

Niektóre zastosowania rentgenowskiej tomografii komputerowej w geologii

100%

Zalewska J. , Dohnalik M.

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2008

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tom R. 64, nr 9

547-556

PL

Rentgenowska tomografia komputerowa (CT) jest techniką posiadającą ogromne możliwości zastosowania w różnych dyscyplinach nauk o ziemi. Ujawnia ona wewnętrzną strukturę obiektów, determinowaną przez różnicę w gęstości. Można na jej podstawie uzyskać duże ilości równoległych przekrojów 2D, które umożliwiają trójwymiarowe odwzorowanie wybranych właściwości. Najważniejszymi zastosowaniami są badania porowatości i możliwości transportowania płynów; stosowane w badaniach geologii naftowej, mechaniki skalnej i gleboznawstwie. W pracy przytoczono trzy szczególnie interesujące przypadki zastosowania x-ray CT w badaniach rdzeni wiertniczych.

EN

Roentgen computed tomography (CT) is a technique with wide application capabilities in many disciplines of earth sciences. It reveals internal object structure determined by density differences. This technique allows obtaining many 2D parallel slices, which enable spatial imaging of some features. Most important applications are porosity measurements and fluid transport capabilities which are used in oil geology researches, rock mechanics and soil science. This article shows three interesting x-ray CT applications in rock core researches.

2

Algorytm wyznaczania ścieżki nawigacyjnej do automatycznego ruchu wirtualnej kamery w strukturach anatomicznych

100%

Skalski A. , Socha M. , Duplaga M.

Pomiary Automatyka Kontrola

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2007

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tom R. 53, nr 9 bis

421--424

PL

W pracy przedstawiono nowy algorytm wyznaczania centralnej ścieżki nawigacyjnej w trójwymiarowych danych pochodzących z tomografii komputerowej. Algorytm wykorzystuje transformacje odległości, iteracyjny schemat przetwarzania charakterystycznych punktów ścieżki oraz interpolację metodą cubic spline do wyznaczeni gładkiej przestrzennej krzywej nawigacyjnej. Wygenerowanie ścieżki pozwala lekarzowi na łatwe przeglądanie przestrzennego komputerowego modelu struktur anatomicznych, takich jak drzewo oskrzelowe (wirtualna bronchoskopia) czy jelito grube (wirtualna kolonoskopia), a dzięki temu poszerza możliwości diagnostyczne lekarza. W artykule szczegółowo zaprezentowano algorytm przetwarzania danych prowadzący do wyznaczenia ścieżki oraz wyniki działania prezentowanych algorytmów w zastosowaniu do wirtualnej kolonoskopii.

EN

The paper presents a new algorithm of centre path computing of CT data. The algorithm uses distance transformation,characteristic points interaction processing and cubic spline interpolation. The centre path defining allows for easily determination of three-dimensional model of anatomical structures that might be viewed by physician. The described method is a novel approach at enhancing diagnostic capabilities of - for example - bronchial tree (v.b. - virtual bronchoscopy) or colon (v.c. - virtual colonoscopy). The authors present detailed process of practical application of given algorithm, focusing upon v.c.

3

GTV volume estimation using different mode of computer tomography for lung tumors in stereotactic body radiation therapy

94%

Lingaiah R. , Ali M. A. , Kulsum U. , Muneem M. A. , Mani K. R. , Ahmed S. , Rahman M. S. , Salahuddin M.

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tom Vol. 25, Iss. 1

29--34

EN

Aim: To estimate the Gross Tumor Volume (GTV) using different modes (axial, helical, slow, KV-CBCT & 4D-CT) of computed tomography (CT) in pulmonary tumors. Materials & Methods: We have retrospectively included ten previously treated case of carcinoma of primary lung or metastatic lung using Stereotactic Body Radiation Therapy (SBRT) in this study. All the patients underwent 4 modes of CT scan Axial, Helical, Slow & 4D-CT using GE discovery 16 Slice PET-CT scanner and daily KV-CBCT for the daily treatment verification. For standardization, all the patients underwent different modes of scan using 2.5 mm slice thickness, 16 detectors rows and field of view of 400mm. Slow CT was performed using axial mode scan by increasing the CT tube rotation time (typically 3 – 4 sec.) as per the breathing period of the patients. 4D-CT scans were performed and the entire respiratory cycle was divided into ten phases. Maximum Intensity Projections (MIP), Minimum Intensity Projections (MinIP) and Average Intensity Projections (AvIP) were derived from the 10 phases. GTV volumes were delineated for all the patients in all the scanning modes (GTVAX - Axial, GTVHL - Helical, GTVSL – Slow, GTVMIP -4DCT and GTVCB – KV-CBCT) in the Eclipse treatment planning system version 11.0 (M/S Varian Medical System, USA). GTV volumes were measured, documented and compared with the different modes of CT scans. Results: The mean ± standard deviation (range) for MIP, slow, axial, helical & CBCT were 36.5 ± 40.5 (2.29 – 87.0), 35.38 ± 39.52 (2.1 – 82), 31.95 ± 37.29 (1.32 – 66.9), 28.98 ± 33.36 (1.01 – 65.9) & 37.16 ± 42.23 (2.29 – 92). Overall underestimation of helical scan and axial scan compared to MIP is 21% and 12.5%. CBCT and slow CT volume has a good correlation with the MIP volume. Conclusion: For SBRT in lung tumors better to avoid axial and helical scan for target delineation. MIP is a still a golden standard for the ITV delineation, but in the absence of 4DCT scanner, Slow CT and KV-CBCT data may be considered for ITV delineation with caution.

4

Format DICOM – komunikacja pomiędzy systemami diagnostyki obrazowej i planowania leczenia radioterapii

84%

Osewski W. , Dolla Ł. , Hawrylewicz L. , Garbaciok S. , Ślosarek K.

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tom Vol. 3, nr 5

221--225

PL

DICOM (Digital Imaging and Communication in Medicine) to format obrazowania cyfrowego i wymiany obrazów w medycynie, opracowany dla potrzeb ujednolicenia wymiany i interpretacji danych medycznych reprezentujących lub związanych z obrazami diagnostycznymi w medycynie. Format ten, przyjęty przez wszystkich producentów sprzętu medycznego za standard, w dużej mierze pozwala na bezproblemową komunikację i wymianę danych pomiędzy urządzeniami różnych firm. Niestety nie zawsze działa to tak, jak chcieli tego twórcy. Zdarza się, że indywidualny rozwój formatu przez poszczególnych producentów w znacznym stopniu komplikuje wspomnianą komunikację. Było to szczególnie widoczne na styku dwóch dziedzin medycyny: diagnostyki obrazowej i radioterapii. Współczesna radioterapia bazuje na badaniach obrazowych, dlatego wprowadzono zmodyfikowany format zwany DICOM RT, który dedykowany jest radioterapii. Zawiera on między innymi informacje na temat struktur anatomicznych, rozkładów dawek, geometrii źródeł promieniowania. Opracowany standard jest nieustannie rozwijany i udoskonalany. Aktualnie przesyłanie informacji w formacie DICOM jest praktycznie bezproblemowe i pozwala na pracę z zastosowaniem sprzętu różnych producentów, dedykowanego do różnych zadań medycznych.

EN

DICOM (Digital Imaging and Communication in Medicine) is a format developed for unification of exchange and interpretation of medical data representing or associated with diagnostic images in medicine. This format, adopted by all manufacturers of medical equipment as an standard format of medical data, allows for trouble-free communication and exchange of data between devices from different companies. Unfortunately it does not always work as the authors of DICOM format wanted to. It happens that the individual producers development of the format greatly complicates previously mentioned communication. This was particularly evident at the junction of two branches of medicine: diagnostics imaging and radiotherapy. Modern radiotherapy is based on imaging studies, so there was a need to introduce modified format called DICOM RT. It contains information about anatomical structures, dose distributions, the geometry of radiation sources etc. This standard is constantly being developed and improved. At present, the transfer of information in DICOM format is almost trouble-free and allows to work with different manufacturers equipment dedicated to different medical tasks.

5

Tomografia komputerowa CT w zastosowaniach przemysłowych. Cz. I. Idea pomiarów, główne zespoły i ich funkcje

84%

Ratajczyk E.

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tom R. 84, nr 2

111-117

PL

Idea pomiarów tomograficznych opartych na promieniowaniu rentgenowskim X. Budowa tomografów komputerowych CT – główne zespoły i ich funkcje.

EN

Concept of tomograph measurements based on the X-ray radiation. Construction of tomograph computers CT - their main units and functions.

6

Zastosowanie rezonansu magnetycznego w planowaniu leczenia

84%

Garbaciok S. , Osewski W. , Dolla Ł. , Hawrylewicz L. , Ślosarek K.

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2014

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tom Vol. 3, nr 6

299--304

PL

Nadrzędnym celem radioterapii jest wyleczenie, a także polepszenie komfortu jakości życia pacjentów. Aby cel ten został zrealizowany, istotne jest precyzyjne określenie granicy guza w trakcie planowania leczenia. Kolejnym ważnym aspektem jest precyzyjne odtworzenie położenia określonych struktur i narządów podczas planowania leczenia. Mimo że badanie tomografii komputerowej nadal pozostaje podstawową metodą diagnostyczną stosowaną w planowaniu leczenia, coraz częściej stosuje się nowe metody obrazowania: rezonans magnetyczny i pozytronową tomografię emisyjną. Przewagą badania rezonansu magnetycznego nad innymi metodami diagnostycznymi jest doskonała zdolność obrazowania tkanek miękkich (mięśnie, więzadła, ścięgna, nerwy) z dokładnością zbliżoną do atlasów anatomicznych i zmian w ich obrębie (również naczyń krwionośnych), przy jednocześnie zachowanym obrazie struktur kostnych. Korzyści wynikające z stosowania dodatkowych metod obrazowania jest bardzo dużo. Najważniejszą z nich jest polepszenie jakości wizualizacji w planowaniu leczenia.

EN

The main purpose of radiotherapy is to cure patent and to improve his quality of live. To achieve this aim precise definition of shape of the tumor and healthy tissues during treatment planning process is significant. Accurate location of structures, used in treatment planning, is also very important feature. Despite the fact that CT scanning is the primary imaging method used in radiotherapy treatment planning, other imaging modalities such as MRI and PET are increasingly used. Advantage of MRI over other diagnostic methods is excellent for soft tissue imaging capability (e.g. muscles, ligament, tendon, nerves), with an accuracy similar to the anatomical atlases, and changes within them (even blood vessels) preserving the image of bone structures at the same time. There are a lot of benefits of using additional imaging methods, but most important is to improve the visualization process in radiotherapy treatment planning.

7

Methods of reconstructing complex multi-structural anatomical objects with RP techniques

84%

Kudasik T. , Miechowicz S.

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2016

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tom Vol. 64, nr 2

315--323

EN

This article presents reconstruction methods applied to a (geometrically and physically) complex structural object with the use of RP and RT techniques. The methods are innovative due to their hybrid - multi-model and multi-material - approach to reconstruction, as well as the application of multiple technologies. An experimental analysis was conducted to verify the feasibility of rapid prototyping (RP) techniques in the reconstruction of complex internal structures using materials of diverse properties. Some RP techniques offer the possibility of discriminating between diverse objects through the use of different colours. Such models are well-suited for diagnostic purposes, for better visualisation of complex clinical problems, pathological alterations, etc. Nevertheless, they fail to fully reflect physical and mechanical properties of objects, which renders them useful in experimental analysis only to a limited extent. Their basic drawback is that they merely reflect geometrical features of the examined object. The methods discussed in the present article enable modelling multi-object structures in a single process based on the PolyJet Matrix technology and materials of different physical properties by means of a hybrid method. The article also describes the process of modelling complex anatomical structures of soft tissues and bones using models of the maxilla and the mandible as examples. The study is based on data acquired through standard computed tomography (CT). In addition, the article addresses selected aspects of CT acquisition, generation of numerical models composed of several anatomical structures (objects) and fabricating physical multi-object models.

8

Verification of the Computed Tomography Results of Aluminum Alloy Welded Joint

83%

Malicki M. , Sobczak K.

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tom Iss. 10

47--52

EN

Computed tomography (CT) of aluminum welded joint specimen has been performed. On the tomographic cross sections some defects have been found. To verify them the metallography cross sections of welded has been done. It was found that selected defects are micro cracks.

9

On the prediction of X-ray dose deviations and the influence of CT scan protocols

83%

Du Plessis F. C. P.

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2017

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tom Vol. 23, Iss. 3

47--54

EN

Patients undergoing computerized tomography (CT) scans for tumor localization and treatment planning are frequently scanned using pre-set customized exposure protocols for optimal imaging of different anatomical sites. The question arises if these scanning protocols will produce a deviation in the Hounsfield number for a given tissue that can afterwards be used to predict the resulting dose calculation deviation due to this. The question is also if the deviation in the Hounsfield number of a tissue is large enough to affect dose calculation clinically significant. A study was devised in which a RMI phantom was scanned with five different scanning protocols and two CT beam energies at 120 and 135 kV. To assess the effect of insert configuration, Hounsfield number measurements were repeated for high density RMI inserts in the center and outer rings in the phantom. For each material insert the standard deviation of the Hounsfield number was calculated. To assist in dose prediction a series of DOSXYZnrc Monte Carlo calculations were carried out for beam qualities between 6 and 16 MV for a range of Hounsfield numbers calculated for bone and water. This provided information on how the depth dose varied as a function of Hounsfield number variation. Lastly, a series of treatment plans were setup for absorbed dose calculation using the RMI insert electron densities vs Hounsfield relations measured above. The absorbed dose of corresponding plans with the largest Hounsfield number variation were subtracted to find the dose discrepancies. It was found that the dose discrepancies in tissue types could be indicated by the deviation of the Hounsfield number due to different scanning protocols. The calculated dose difference were in all cases within 3%.

10

An in-house step-wedge phantom for the calibration of pixel values in CT localizer radiographs for water-equivalent diameter measurement

83%

Rif’ah S. M. , Anam C. , Sutanto H. , Asiah R. H. , Holid H. , Dougherty G.

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tom Vol. 29, Iss. 1

50--57

EN

Introduction: To develop an in-house acrylic-based step-wedge phantom with several thickness configurations for calibrating computed tomography (CT) localizer radiographs in order to measure the water-equivalent diameter (Dw) and the size-specific dose estimate (SSDE). Method: We developed an in-house step-wedge phantom using 3 mm thick acrylic, filled with water. The phantom had five steps with thicknesses of 6, 12, 18, 24, and 30 cm. The phantom was scanned using a 64-slice Siemens Definition AS CT scanner with tube currents of 50, 100, 150, 200, and 250 mA. The relationship between pixel value (PV) and water-equivalent thickness (tw) was obtained for the different step thicknesses. This was used to calibrate the CT localizer radiographs in order to measure Dw and SSDE. The results of Dw and SSDE from the radiographs were compared with those calculated from axial CT images. Results: The relationship between PV and tw from CT localizer radiographs of the phantom step-wedge produced a linear relationship with R2 > 0.990. The linear relationships of the Dw and SSDE values obtained from CT localizer radiographs and axial CT images had R2 values > 0.94 with a statistical test of p-value > 0.05. The Dw difference between those from CT localizer radiographs and axial CT images was 3.7% and the SSDE difference between both was 4.3%. Conclusion: We have successfully developed a step-wedge phantom to calibrate the relationship between PV and tw. Our phantom can be easily used to calibrate CT localizer radiographs in order to measure Dw and SSDE.

11

A 3D Bayesian Computed Tomography Reconstruction Algorithm with Gauss-Markov-Potts Prior Model and its Application to Real Data

71%

Chapdelaine C. , Mohammad-Djafari A. , Gac N. , Parra E.

Fundamenta Informaticae

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2017

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tom Vol. 155, nr 4

373--405

EN

Iterative reconstruction methods in Computed Tomography (CT) are known to provide better image quality than analytical methods but they are not still applied in many fields because of their computational cost. In the last years, Graphical Processor Units (GPU) have emerged as powerful devices in order to parallelize calculations, but the efficiency of their use is conditionned on applying algorithms that can be massively parallelizable. Moreover, in non-destructive testing (NDT) applications, a segmentation of the reconstructed volume is often needed in order to have an accurate diagnosis on the material health, but performing a segmentation after the reconstruction introduces uncertainties in the diagnosis from both the reconstruction and the segmentation algorithms. In this paper, we propose an iterative reconstruction method for 3D CT that performs a joint reconstruction and segmentation of the controlled object in NDT for industrial applications. The method is based on a 3D Gauss-Markov-Potts prior model in Bayesian framework, which has shown its effective use in many image restoration and super-resolution problems. First, we briefly describe this model, before deriving the expression of the joint posterior distribution of all the unknowns. Next, an effective maximization of this distribution is presented. We use a ray-driven projector and a voxel-driven backprojector implemented on GPU. The algorithm is developed so it can be massively parallelized. Finally, we present our results on simulated and real phantoms. In addition, we investigate further reconstruction quality indicators in order to compare our results with other methods.

12

Healed or non-healed? Computed tomography (CT) visualisation of morphology of bite trace ichnotaxa on a dinosaur bone

71%

Jacobsen A. R. , Lauridsen H. , Fiirgaard B. , Boel L. W. T. , Hansen K.

Annales Societatis Geologorum Poloniae

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2015

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tom Vol. 85, No. 3

457--464

EN

Bite traces on fossilised bones can provide important information on predator-prey relations and interactions in ancient environments. In 2009, two new ichnotaxa, Linichnus serratus and Knethichnus parallelum, were introduced to develop the application of bite traces as an ichnological tool. Ichnotaxa defined by theropod bite traces can provide useful information for understanding feeding behaviour. However, objective interpretation of possible bite traces can be difficult using traditional visual inspection. In this study, the bite traces on a fossilised dinosaur bone were comprehensively examined by correlating traditional naked-eye in spection with computed tomography (CT) imaging, used to visualise the internal morphology of the bite traces and in particular, to clarify the appearance of one possibly healed bite trace. A forensic pathologist visually examined the bone with the aid of stereomicroscopy and a radiologist analysed the CT scans. Sixteen different scanner settings were used to optimise the CT parameters and avoid signal at tenuation, in the form of hypointense artefacts in the central trabeculated part of the bone fragment. The use of CT scanning provided information on internal morphology from the vicinity of the bite trace, including hyperdense zones, not identified using visual inspection alone. By applying the extended CT scale, the dense and radiopaque cortical bone layer could be clearly identified and applied as a pathomorphological marker to correctly distinguish non-healed from healed wounds. In conclusion, the authors demonstrate that external visual examination of trace fossils by ichnologists in combination with interior examination using CT imaging can be applied to characterise ichnotaxa defined by bite traces and potentially provide clues on ancient feeding behaviour.

13

X-ray Computed Tomography using a Sparsity Enforcing Prior Model Based on Haar Transformation in a Bayesian Framework

71%

Wang L. , Mohammad-Djafari A. , Gac N.

Fundamenta Informaticae

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2017

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tom Vol. 155, nr 4

449--480

EN

X-ray Computed Tomography (CT) has become a hot topic in both medical and industrial applications in recent decades. Reconstruction by using a limited number of projections is a significant research domain. In this paper, we propose to solve the X-ray CT reconstruction problem by using the Bayesian approach with a hierarchical structured prior model basing on the multilevel Haar transformation. In the proposed model, the multilevel Haar transformation is used as the sparse representation of a piecewise continuous image, and a generalized Student-t distribution is used to enforce its sparsity. The simulation results compare the performance of the proposed method with some state-of-the-art methods.

14

Validation of microscopy measured porosity in carbon fibbers composites

71%

Jędral A. , Bona A.

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tom Vol. 26, No. 4

83--90

EN

One of the most common defects in carbon fibrereinforced plastics (CFRP) is porosity. Too much of those defectscould be serious problemsto mechanical properties, which directly take effect on elements safety, like aircrafts. Therefore, the evaluation of porosity is very important test. Microscopic observations are widely used as a quality instrument in materials and constructions inspections. Cross section image of a material is easy to prepare and analyse. Porosity of a carbon fibrereinforced plasticcan be clearly spot in such kind of images. Study shows that in the most cases porosity appear between layers of fibres , rather between fibres. Unfortunately,image from microscope is only 2D picture from a small representative region. Because of that,comparison of 2D image to a real porosity distribution in all volume of a material is very difficult. To verify 2D microscopic observation method is necessary to perform another kind of tests. In this article , authors focused on non-destructive (NDT) and destructive testing methods. 2D porosity images from light microscope were compared with three different testing methods: ultrasonic test (UT), computed tomography (CT) test and constituent content of composite materials standard test method according to ASTM D3171 – 15, procedure B. Porosity results obtained from dissolution of resin from the carbon-epoxy resin sample.

15

Evaluation of mandibular geometry in healthy children aged 0-1 year - a pilot study

71%

Lipowicz A. , Kawlewska E. , Larysz D. , Kostyra P. , Graja K. , Joszko K. , Gzik-Zroska B. , Wolański W.

Acta of Bioengineering and Biomechanics

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2023

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tom Vol. 25, no. 3

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.

16

Virtual and material models of human thoracic-lumbar spine with compressive fracture based on patients' CT data and the rapid prototyping technique

67%

Dąbrowska-Tkaczyk A. , Floriańczyk A. , Grygoruk R. , Skalski K. , Borkowski P.

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2011

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tom Vol. LVIII, nr 4

425-440

EN

The paper presents the development procedures for both virtual 3D-CAD and material models of fractured segments of human spine formulated with the use of computer tomography (CT) and rapid prototyping (RP) technique. The research is a part of the project within the framework of which a database is developed, comprising both 3D-CAD and material models of segments of thoracic-lumbar spine in which one vertebrae is subjected to compressive fracture for a selected type of clinical cases. The project is devoted to relocation and stabilisation procedures of fractured vertebrae made with the use of ligamentotaxis method. The paper presents models developed for five patients and, for comparison purposes, one for a normal spine. The RP material models have been built basing on the corresponding 3D-CAD ones with the use of fused deposition modelling (FDM) technology. 3D imaging of spine segments in terms of 3D-CAD and material models allows for the analysis of bone structures, classification of clinical cases and provides the surgeons with the data helpful in choosing the proper way of treatment. The application of the developed models to numerical and experimental simulations of relocation procedure of fractured vertebra is planned.

PL

W pracy zostały przedstawione procedury opracowania modeli wirtualnych i materialnych uszkodzonych, w efekcie urazów lub długotrwałej patologii, odcinków kręgosłupa pacjentów oraz przykłady wykonanych modeli. Przedstawione w pracy modele wirtualne opracowano na podstawie danych CT pięciu pacjentów oraz jednego przypadku odcinka kręgosłupa prawidłowego. Tworzona jest tym samym baza danych modeli segmentów kręgosłupa piersiowo-lędźwiowego z jednym trzonem złamanym kompresyjnie dla wybranej klasy przypadków klinicznych. Modele te posłużyły następnie do wykonania ich odpowiedników materialnych w technice szybkiego wytwarzania prototypów (rapid rototyping - RP). Zastosowana została technologia FDM (fused deposition modeling). Wizualizacja segmentów lub odcinków kręgosłupa poprzez tworzenie modeli wirtualnych i materialnych daje możliwość analizy struktur kostnych, klasyfikacji i oceny przypadków oraz rozważenie możliwych wariantów leczenia urazu. Przewiduje się wykorzystanie opracowanych modeli do przeprowadzenia numerycznej oraz doświadczalnej symulacji nastawiania odłamów złamanego trzonu. Praca jest częścią realizacji projektu dotyczącego procedur leczenia, nastawiania i stabilizacji złamanego trzonu kręgu metodą ligamentotaksji.

17

Analysis of mechanical properties and structure of samples filled with continuous glass fiber produced in composite filament fabrication technology

67%

Marciniak D. , Sykutera D. , Czyżewski P.

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tom Vol. 72, nr 2

art. no. e148841

EN

The purpose of the study was to evaluate selected mechanical properties and structural characteristics of samples manufactured using composite filament fabrication (CFF) technology from Onyx material, whichwas filled with continuous glass fiber. Selected mechanical properties were correlated with the density of the resulting composite to determine the specific strength of the fabricated parts. The test specimens were manufactured on a Mark Two Enterprise machine (Markforged, USA) using composite filament fabrication (CFF) technology. The material used was polyamide 6.6 with a 20% short carbon fiber content with the trade name Onyx. Continuous glass fiber was used to reinforce the fabrication. The density of the manufactured samples was determined using a hydrostatic method. Methanol was used as the liquid. By determining the density of the samples, it was possible to estimate through appropriate calculations what specific strength and specific modulus the obtained composites would have. Determination of tensile and flexural strengths was carried out in accordance with ISO 527-1:2012 and ISO 178:2003. Determination of the impact tensile strength of the samples was carried out in accordance with ISO 8256, the beams were tested using the A method. Due to the high impact tensile strength, two 1 mm notches with an angle of 45°were made on the specimens. The image of the sample structure obtained by the CFF method was recorded using a CT scanner. A thermogravimetric test (TG) of the Onyx matrix material was carried out. The samples were tested approximately 72 hours after fabrication. Filling the samples with continuous glass fiber above 50% leads to a slight increase in impact resistance. The density of the composite increased by only 16% relative to the reference samples, resulting in a 389% increase in the maximum average flexural strength. Despite significant discontinuities in the structure of the produced composite, it was possible to record an increase in tensile strength and Young’s modulus by 606% and 370%, respectively.

18

Flaw Detection of Cast-Steel Safety Parts in Automotive Application

67%

Dizdar K. C. , Sahin H. , Ardicli M. , Dispinar D.

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tom Vol. 22, iss. 1

13--17

EN

Casting is the most economical way of producing parts for many industries ranging from automotive, aerospace to construction towards small appliances in many shares. One of the challenges is the achievement of defect-free cast parts. There are many ways to do this which starts with calculation and design of proper runner system with correct size and number of feeders. The first rule suggests starting with clean melt. Yet, rejected parts can still be found. Although depending on the requirement from the parts, some defects can be tolerated, but in critical applications, it is crucial that no defect should exist that would deteriorate the performance of the part. Several methods exist on the foundry floor to detect these defects. Functional safety criteria, for example, are a must for today's automotive industry. These are not compromised under any circumstances. In this study, based on the D-FMEA (Design Failure Mode and Effect Analysis) study of a functional safety criterion against fuel leakage, one 1.4308 cast steel function block, which brazed-on fuel rail port in fuel injection unit, was investigated. Porosity, buckling, inclusion and detection for leak were carried out by non-destructive test (NDT) methods. It was found that the best practice was the CT-Scan (Computed Tomography) for such applications.

19

Three dimensional finite element analysis of a novel osteointegrated dental implant designed to reduce stress peak of cortical bone

59%

Zheng L. , Yang J. , Hu X. , Luo J.

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tom Vol. 16, no. 3

21--28

EN

A new type of dental implant was designed as multi-component mainly including inset and abutment between which a gap was introduced to guide the force to transmit from the cancellous bone to cortical bone, with the intention to lower the stress peak at cortical bone. By the way of finite element analysis (FEA) associated with advanced computer tomography (CT) and 3D model reconstruction technology to construct precise mandible model, biomechanical aspects of implant were investigated. Compared with traditional implant that created stress dominantly at cortical bone, stress peak at the implant/bone interface in the cervical cortex decreased sharply (about 51%) for new type of implant. Furthermore, varying implant shape and gap dimensions to optimize the design of this new implant was performed. Optimization results revealed that: 1) screwed cylindrical implant is superior to tapered, stepped and smooth cylindrical implant in effectively decreasing the stress peak of bone; 2) deepening and widening gap would contribute to the decline of stress peak, but at the cost of break and destruction of the inset; 3) suitable gap size with the depth of 7mm and width of 0.3mm would be applicable. This work may provide reference forclinical application of dental implant.

20

Zastosowanie metody chan-vese w segmentacji obrazów medycznych

59%

Prokop P.

|

tom nr 4

32--37

PL

W artykule przedstawiono problem wyznaczania krawędzi obiektów zamkniętych w obrazach medycznych CT, które będą podlegały dalszej analizie, na potrzeby diagnostyki medycznej. Zastosowanie przekształcenia, które wprowadza progowanie, pozwala na wyeliminowanie pikseli prezentujących obiekty dla tkanek, które nie podlegają dalszej analizie. Podejście to pozwoliło na wyostrzenie krawędzi obiektów prezentujących tkanki miękkie. Porównano sposób wykrycia krawędzi tkanek miękkich, dla obrazu pierwotnego i przetworzonego za pomocą przekształcenia, z zastosowaniem metody Chan-Vese. Wyostrzenie krawędzi obrazu poprawiło dokładność wykrywania obiektów prezentujących tkanki miękkie.

EN

The article presents the problem of determining the edges of objects enclosed in a medical CT images, which will be subject to further analysis, for the purpose of medical diagnosis. The use of a transformation which introduces two-point thresholding, eliminates presenting pixels of objects for tissues that are not a subject to further analysis. This approach allowed us to sharpen the edges of objects presenting soft tissue. A way to detect the edge of the soft tissue was compared for the original image and processed one using the transformation using the method of Chan-Vese. Sharpening of edges of the image have improved the accuracy of detection of objects presenting the soft tissue.