83 research outputs found

    Restoration and preservation of the reinforced concrete poles of fence at the former Auschwitz concentration and extermination camp

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    AbstractThe objective of this study was to assess the present state of the reinforced concrete poles of fence at the former Auschwitz I and Auschwitz II-Birkenau concentration and extermination camp. The poles were subjected to renovation about 10 years ago. After this time some deficiencies of applied renovation method were noticed. Cracks appeared between fresh and original part of concrete cover. Analysis of the reasons of these failures was performed and a modification of used restoration method was proposed to overcome this deficiency. The modification consists in application of sacrificial anodes mounted outside the pole, in soil and inside the concrete cover

    Effects of 60 MeV protons and 250 kV X-rays on cell viability

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    Particle radiotherapy such as the one using proton beams, provides a successful treatment approach in many cancer types. However, the cellular and molecular mechanisms by which proton irradiation induces cell death, particularly in a human peripheral blood lymphocyte model has not been examined in detail. Comparative studies of the biological effects, such as cell death, of particle therapy versus conventional X-rays treatment are of utmost importance. Here, we compared the viability of human peripheral blood lymphocyte following in vitro irradiation with protons (therapeutic 60 MeV proton beam) and photon beam (250 kV, X-rays), by applying separate doses within the range of 0.3-4.0 Gy. Cell viability was assessed 1 and 4 h after irradiation with protons and X-rays by the FITC-Annexin V labelling procedure (Apoptotic & Necrotic & Healthy Cells Quantification Kit, Biotium). Results showed that irradiation with both radiation types reduced the number of viable cells in a dose-dependent manner, as assessed as a function of the duration of post-irradiation time. Protons proved more fatal to the cells treated than X-ray photons. This demonstrates a difference in cell viability after irradiation with protons and photons in a human peripheral blood lymphocyte model

    Refining Critical Structure Contouring in STereotactic Arrhythmia Radioablation (STAR): Benchmark Results and Consensus Guidelines from the STOPSTORM.eu Consortium.

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    BACKGROUND AND PURPOSE In patients with recurrent ventricular tachycardia (VT), STereotactic Arrhythmia Radioablation (STAR) shows promising results. The STOPSTORM consortium was established to investigate and harmonise STAR treatment in Europe. The primary goals of this benchmark study were to standardise contouring of organs at risk (OAR) for STAR, including detailed substructures of the heart, and accredit each participating centre. MATERIALS AND METHODS Centres within the STOPSTORM consortium were asked to delineate 31 OAR in three STAR cases. Delineation was reviewed by the consortium expert panel and after a dedicated workshop feedback and accreditation was provided to all participants. Further quantitative analysis was performed by calculating DICE similarity coefficients (DSC), median distance to agreement (MDA), and 95th percentile distance to agreement (HD95). RESULTS Twenty centres participated in this study. Based on DSC, MDA and HD95, the delineations of well-known OAR in radiotherapy were similar, such as lungs (median DSC=0.96, median MDA=0.1mm and median HD95=1.1mm) and aorta (median DSC=0.90, median MDA=0.1mm and median HD95=1.5mm). Some centres did not include the gastro-oesophageal junction, leading to differences in stomach and oesophagus delineations. For cardiac substructures, such as chambers (median DSC=0.83, median MDA=0.2mm and median HD95=0.5mm), valves (median DSC=0.16, median MDA=4.6mm and median HD95=16.0mm), coronary arteries (median DSC=0.4, median MDA=0.7mm and median HD95=8.3mm) and the sinoatrial and atrioventricular nodes (median DSC=0.29, median MDA=4.4mm and median HD95=11.4mm), deviations between centres occurred more frequently. After the dedicated workshop all centres were accredited and contouring consensus guidelines for STAR were established. CONCLUSION This STOPSTORM multi-centre critical structure contouring benchmark study showed high agreement for standard radiotherapy OAR. However, for cardiac substructures larger disagreement in contouring occurred, which may have significant impact on STAR treatment planning and dosimetry evaluation. To standardize OAR contouring, consensus guidelines for critical structure contouring in STAR were established

    Adherence measurements and corrosion resistance in primer/hot-dip galvanized steel systems

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    This paper focuses on the adherence during ageing of a primer (made of polyester resins crosslinked with melamine) applied onto hot-dip galvanized (HDG) steel for coil coating application and its influence on corrosion protection. A chromium-free surface treatment, composed of fluorotitanic acid, phosphoric acid, manganese phosphate, and vinylphenol was applied on the HDG steel to obtain high corrosion resistance and high adherence of a polyester and melamine primer. The influence of the manganese phosphate on the corrosion and adherence was investigated. To measure the adherence between the metal and the primer, a three-point flexure test was set up. The adherence was then linked with corrosion resistance during ageing, using electrochemical impedance spectroscopy

    Deformation Microstructure And Texture Transformations In FCC Metals Of Medium-To-High Stacking Fault Energy: Critical Role Of Micro- And Macro-Scale Shear Bands

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    Microstructure and texture development in medium-to-high stacking fault energy face centred cubic metals were investigated in order to examine the role of lattice re-orientation on slip propagation across grain boundaries and to characterize the influence of micro- and macro-scale copper-type shear bands on textural changes at large deformations. Polycrystalline pure copper (fine - and coarse - grained) and fine-grained AA1050 alloy were deformed in plane strain compression at room temperature to form two sets of well-defined macroscopic shear bands. The deformation-induced sub-structures and local changes in crystallographic orientations were investigated mostly by scanning electron microscopy equipped with high resolution electron backscattered facility. In all the deformed grains within macro- shear bands a strong tendency to strain-induced re-orientation was observed. The flat, strongly deformed grains exhibited a deflection within narrow areas. The latter increased the layers’ inclination with respect to ED and led to kink-type bands, which are the precursors of MSBs. The mechanism of macro- / micro-shear bands formation is strictly crystallographic since in all the areas of the sheared zone, the crystal lattice rotated such that one of the {111} slip planes became nearly parallel to the shear plane and the direction became parallel to the direction of maximum shear. This strain-induced crystal lattice rotation led to the formation of specific macro- / micro-shear bands components that facilitated slip propagation across the grain boundaries without any visible variation in the slip direction

    Zmiany mikrostrukturalne i teksturowe w odkształconych metalach o sieci RSC o średniej i wysokiej energii błędu ułożenia: krytyczna rola mikro- i makro-pasm ścinania

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    Microstructure and texture development in medium-to-high stacking fault energy face centred cubic metals were investigated in order to examine the role of lattice re-orientation on slip propagation across grain boundaries and to characterize the influence of micro- and macro-scale copper-type shear bands on textural changes at large deformations. Polycrystalline pure copper (fine - and coarse - grained) and fine-grained AA1050 alloy were deformed in plane strain compression at room temperature to form two sets of well-defined macroscopic shear bands. The deformation-induced sub-structures and local changes in crystallographic orientations were investigated mostly by scanning electron microscopy equipped with high resolution electron backscattered facility. In all the deformed grains within macro- shear bands a strong tendency to strain-induced re-orientation was observed. The flat, strongly deformed grains exhibited a deflection within narrow areas. The latter increased the layers’ inclination with respect to ED and led to kink-type bands, which are the precursors of MSBs. The mechanism of macro- / micro-shear bands formation is strictly crystallographic since in all the areas of the sheared zone, the crystal lattice rotated such that one of the {111} slip planes became nearly parallel to the shear plane and the direction became parallel to the direction of maximum shear. This strain-induced crystal lattice rotation led to the formation of specific macro- / micro-shear bands components that facilitated slip propagation across the grain boundaries without any visible variation in the slip direction.W pracy badano zmiany strukturalne i teksturowe w metalach o sieci regularnej ściennie centrowanej związane z lokalną re-orientacją sieci krystalicznej wynikającą z formowania się mikro- i makro- pasm ścinania. Analizowano polikrystaliczne próbki miedzi oraz aluminium o czystości technicznej (stop AA1050) odkształcane w temperaturze otoczenia w próbie nieswobodnego ściskania do zakresu odkształceń, w których następuje wyraźne uformowanie się dwóch rodzin makroskopowych pasm ścinania. W badaniach wykorzystano skaningowy mikroskop elektronowy wyposażony w system automatycznego pomiaru orientacji lokalnych. Zaobserwowano, że w ziarnach umiejscowionych w obszarze makroskopowych pasm ścinania występuje ściśle zdefiniowana tendencja rotacji sieci krystalicznej, w wyniku której jedna z płaszczyzn typu {111} przyjmuje położenie zbliżone do położenia płaszczyzny ścinania, a jeden z kierunków typu (lub ) wykazuje tendencję do sytuowania się równolegle do kierunku ścinania. Obserwowana w obszarze wnętrza pasm ścinania rotacja prowadzi do uformowania się specyficznej (mikro)tekstury, która umożliwia propagację poślizgów poprzez granice ziaren bez ‘istotnej’ zmiany kierunku ścinania
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