Prerequisites for precipitate cracking in a yielding ductile matrix have been examined. A statistical model based on the fibre loading model combined with weakest link fracture theory is presented. With the model it is possible to estimate the effect of different variables on the particle fracture probability quantitatively. The predictions made are in excellent agreement with experimental results for a variety of different precipitate types. The result can be applied to calculate the probability of cleavage fracture for steels.
Background: Paramedics face end-of-life care patients during emergency calls and more recently through planned protocols. However, paramedics experiences and educational needs concerning preplanned end-of-life care at home remain largely unknown. Aim: To describe experiences and educational needs of the paramedics included in the end-of-life care protocol. Design: A mixed method study with a questionnaire including open ended questions and numeric evaluations on a Likert scale. Setting/Participants: The questionnaire was delivered to and answered by all the 192 paramedics working in North Karelia fire and rescue department during the time of the data collection in 2017. Results: Over 80% of the paramedics agreed that the protocol helped them to take care of the patients and to improve the quality of end-of-life care. Visits to the patients were considered useful and the end-of-life care as a meaningful work by 76.5% and 62.5% of the paramedics, respectively. The paramedics expressed challenges in psychosocial aspects, communication, symptom management, and their role in end-of-life care. Encountering and communication with the families as well as managing the most common symptoms were emphasized as educational needs. Using a patient controlled analgesia device emerged as an example of practical educational aspect. Conclusions: Paramedics considered end-of-life care at home meaningful but called for more competency in supporting and encountering the families and in symptom management. Our results can be utilized when developing end-of-life care protocols and education for the paramedics. Patients’ and families’ views on the paramedics’ participation in end-of-life care should be evaluated in the future.
The microstructural basis of the critical tensile stress criterion of cleavage fracture is discussed. It is shown that cleavage can be carbide induced in bainitic steels as well as in ferritic steels. The plastic work expended in brittle crack propagation is shown to be somewhat smaller for bainitic steels than for ferritic steels. This is proposed to be caused by the much higher dislocation density of the bainitic microstructure. The statistical nature of the cleavage fracture initiation process is shown to result in a test piece geometry dependent cleavage fracture stress.
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