104 research outputs found

    A novel method of experimental determination of grain stresses and critical resolved shear stresses for slip and twin systems in a magnesium alloy

    Get PDF
    A novel original method of determination of stresses and critical resolved shear stresses (CRSSs) using neutron diffraction was proposed. In this method, based on the crystallite group method, the lattice strains were measured in different directions and using different reflections hkl during uniaxial deformation of magnesium alloy AZ31. The advantage of this method is that the stresses for groups of grains having similar orientations can be determined directly from measurement without any models used for data interpretation. The obtained results are unambiguous and do not depend on the models assumptions as in previous works. Moreover, it was possible for the first time to determine the uncertainty of the measured CRSS values and local stresses at groups of grains. The used methodology allowed for the determination of stress partitioning between grains having different orientations and for an explanation of the anisotropic mechanical behaviour of the strongly textured alloy. Finally, the CRSS values allowed for the validation of the type of intergranular interaction assumed in the elastic–plastic self-consistent model and for a significant reduction of the number of unknown parameters when the model is adjusted to the experimental data

    A novel method of experimental determination of grain stresses and critical resolved shear stresses for slip and twin systems in a magnesium alloy

    Full text link
    A novel original method of determination of stresses and critical resolved shear stresses (CRSSs) using neutron diffraction was proposed. In this method, based on the crystallite group method, the lattice strains were measured in different directions and using different reflections hkl during uniaxial deformation of magnesium alloy AZ31. The advantage of this method is that the stresses for groups of grains having similar orientations can be determined directly from measurement without any models used for data interpretation. The obtained results are unambiguous and do not depend on the models assumptions as in previous works. Moreover, it was possible for the first time to determine the uncertainty of the measured CRSS values and local stresses at groups of grains. The used methodology allowed for the determination of stress partitioning between grains having different orientations and for an explanation of the anisotropic mechanical behaviour of the strongly textured alloy. Finally, the CRSS values allowed for the validation of the type of intergranular interaction assumed in the elastic-plastic self-consistent model and for a significant reduction of the number of unknown parameters when the model is adjusted to the experimental data.Comment: 61 pages, 31 figures, 6 pages in Appendix, Accepted in Measuremen

    The hardening in alloys and composites and its examination with a diffraction and self-consistent model

    Get PDF
    The paper presents the results of diffraction stress measurement in Al/SiC composite and in 2124T6 aluminum alloy during the in situ tensile test. The main aim of the work is to observe the stress values for different stages of tensile test for the composite after applying two types of thermal treatment and for the alloy used as a matrix in this composite, to identify the type of hardening process. The experimental results were compared against the calculations results obtained from the self-consistent model developed by Baczmański [1] - [3] to gain the information about the micromechanical properties (critical resolved shear stress τcr_{cr} and hardening parameter H) of the examined materials. This comparison allowed researchers to determine the role of reinforcement in the composite as well as the impact of the heat treatment on the hardening of the material

    A micro-CT study of the sinus tympani variation in humans

    Get PDF
    The posterior part of the tympanic cavity comprises a depression called the sinus tympani (ST). The said structure is of outmost importance, e.g., in surgical procedures involving the middle ear, as a pathology (microbial biofilm or cholesteatoma) present in this difficult to access location might hinder its effective treatment. The aim of the study was to evaluate anatomical variants of the sinus tympani in human adult petrous bones. For this purpose, 3D models of the ST were recreated from micro-CT scans of 44 dry petrous bone samples (19 female, 25 male), applying 3D Slicer, Meshmixer and MeshLab softwares. Anatomical variants of the ST were classified in terms of both shape and surface configuration. The internal configuration of the ST was classified as heterogeneous - containing small bony trabeculae and crests up to 1.0 mm in size, contrasting to homogeneous ST that characterizes a relatively smooth interior, or mere presence of minor depressions and mild folds. Female STs were more bowl-shaped (57.9%) than saccular (42.1%), and had heterogeneous surface configuration (52.6%) compared to homogeneous (47.4%). On the contrary, male STs were more saccular (52.0%) rather than bowl-shaped (48.0%), and predominantly had a heterogeneous surface (84.0%) over homogeneous (16.0%). A complex combination of ST features comprised of a saccular shape and heterogeneous surface occurred in 52.0% of males and in 15.8% of females (a statistically significant difference; p = 0.0254, Fisher’s exact test) seems to be clinically important because of its potential negative implication on health outcomes after surgery in case of e.g., cholesteatoma, and it may also favor chronic pathological processes

    Seelsorge in einer sich verändernden polnischen Gesellschaft

    Get PDF
    polska wersja artykułu opublikowanego po niemieckuProwadzone od wieków przez zakony, stowarzyszenia i fundacje chrześcijańskie szpitale, domy pomocy, ośrodki Caritasu i ochronki zostały znacjonalizowane w Polsce i Europie Wschodniej po 1945 roku. Jednocześnie z oddaleniem związków wyznaniowych od opieki medycznej i pomocy społecznej malał prestiż zawodów medycznych i pomocowych oraz marksistowska ideologizacja środowiska. Opór integrował w Polsce te środowiska e z Kościołem katolickim, przypominającymi o etyce chrześcijańskiej i deontologii opartej na chrześcijańskim personalizmie. Solidarność Służby Zdrowia i postulaty dotyczące powrotu do etyki zawodów medycznych oraz przywrócenia funkcji kapelanów szpitali i instytucji pomocy społecznej znalazły się w Rozporządzeniu Ministra Zdrowia z 1981 roku. Do 1989 roku w Polsce obszarem, w którym na styku ochrony zdrowia, pomocy społecznej, wolontariatu i związków wyznaniowych, rozwijała się opieka duchowo-religijna, były wolontaryjne zespoły domowej opieki hospicyjnej. Ich przykład pomógł w procesie odbudowy opieki duchowo-religijnej w ochronie zdrowia i pomocy społecznej, a także w nowych inicjatywach zespołowej opieki duszpasterskiej. Współczesne polskie społeczeństwo jest jednym z najbardziej religijnych w Europie, a dominującą religią jest katolicyzm. Wobec zmian społecznych i kulturowych ważna jest wrażliwość wobec zmieniających się potrzeb duchowo-religijnych i różny stopień przynależności pacjentów do wspólnot wiary. Świdomość różnorodności wyznaniowej i kulturowej, rozróżnienie potrzeb duchowych, uznawanych za jedną z powszechnych potrzeb każdej osoby, od potrzeb religijnych, związanych z przynależnością do danej wspólnoty wiary jest wyzwaniem w pastoralnej opiece w warunkach instytucjonalnych i domowych.Charitable institutions, carried out for centuries by religious orders, associations and foundations Christian hospitals, nursing homes, Caritas centers were nationalized in Poland and Eastern Europe after 1945. Simultaneously with the remoteness of religious associations of medical care and social assistance diminish the prestige of the medical profession and Marxist ideologisation of caring environment. Resistance integrated those careers in Poland with the Catholic Church, reminiscent of Christian ethics and professional conduct based on Christian personalism. Solidarity demanded return to ethics of the medical profession and to restore the chaplains of hospitals and social assistance institutions. It was included in the Regulation of the Minister of Health in 1981. Until 1989 in Poland, an area in which to contact the health, social welfare, voluntary and religious organizations, developed health spiritual-religious, volunteer teams were home hospice care. Their example helped in the reconstruction process of spiritual and religious care in health care and social assistance, as well as new initiatives in the pastoral care teams. The contemporary Polish society is one of the most religious in Europe, and the dominant religion is Catholicism. To change the social and cultural importance of sensitivity to the changing needs of the spiritual-religious and different degree of membership subjects to the faith communities. Awareness of diversity of religious and cultural distinction spiritual needs, recognized as one of the common needs of each person, from religious needs, relating to participation in the faith community is a challenge in pastoral care in institutional settings and home care
    corecore