The overall objective is a top-down approach to structural instability phenomena in wind turbine blades, which is used to identify the physics governing the ultimate strength of a generic wind ...turbine blade under a flap-wise static test. The work is concerned with the actual testing and the adoption of a phenomenological approach, and a discussion is conducted to assess and evaluate the wind turbine blade response during loading and after collapse by correlating experimental findings with numerical model predictions. The ultimate strength of the blade studied is governed by instability phenomena in the form of delamination and buckling. Interaction between both instability phenomena occurs causing a progressive collapse of the blade structure.
The objective of this paper is to present a geometrical nonlinear and interlaminar progressive failure finite element analysis of a generic wind turbine blade undergoing a static flap-wise load and ...comparisons with experimental findings. It is found that the predictive numerical models show excellent correlation with the experimental findings and observations in the pre-instability response. Consequently, the ultimate strength of the wind turbine blade studied is governed by a delamination and buckling coupled phenomenon, which results in a chain of events and sudden structural collapse with compressive fibre failure in the delaminated flange material. Finally, a parametric study of the critical load factors with respect to various delamination sizes and positions inside the compressive flange of the wind turbine blade is presented.
Deposition of aerosol nanoparticles using an electrostatic precipitator is widely used in the aerosol community. Despite this, basic knowledge regarding what governs the deposition has been missing. ...This concerns the prediction of the size of the particle collection zone, but also, perhaps more importantly, prediction of the nanoparticle concentration distribution on the substrate, both of which are necessary to achieve faster and more precise deposition. In this article, we have used COMSOL Multiphysics simulations, experimental depositions, and two analytical models to describe the deposition. Based on that, we propose a simple equation that can be used to predict the size of the deposition spot as well as the particle concentration on the substrate. The equation we derive concludes that the size of the deposition spot only depends on the gas flow rate into the precipitator, and on the constant drift velocity of a particle in an electric field. The equation also displays that the deposited particle concentration is independent of the gas flow rate. Our general mathematical analysis has great applicability, as it can be used to model different geometries and different types of deposition methods than the one described in this article. We can therefore also propose that the drift velocity in this model easily could be replaced by another velocity acting on the particles at other deposition conditions, for instance, the thermophoretic velocity during thermophoretic deposition. This would result in the same dependence as presented in this article. Finally, we demonstrate analytically and through experiment that the particle distribution inside the spot will be homogenous and follows a top hat profile.
A unidirectional glass fiber/epoxy composite was characterized under multi-axial loading by testing off-axis specimens under uniaxial tension and compression at various angles relative to the fiber ...direction. Iosipescu shear tests were performed with both symmetric and asymmetric specimens. Tests were performed on both 1-2 and 1-3 material coordinate planes. Strain gauges and Digital Image Correlation were used to record the stress–strain responses. A new approach was used to define a ‘failure initiation strength’ by analyzing the recorded stress–strain curves. The experimentally determined failure stresses were compared with the predictions of the maximum stress, Tsai-Wu and Northwestern University failure criteria. It was found that using the approach of analyzing the stress–strain curve to define a point of material failure initiation, it was possible to obtain good correlation between the experimental data and predictions by both the Tsai-Wu and the NU failure criteria.
Abstract
Background
Involving relevant stakeholders in development or improvement of community health services is rapidly increasing and found to be of pivotal importance for the success of the ...service. Involvement can help identify priorities, understand the problem, and find solutions. However, frail older people are often hard to reach, and can be an underrepresented group in terms of involvement in community health services. If community health services targeted frail older people, are expected to benefit their health and well-being, the voices of this group need to be heard and taken into consideration.
The objective was to involve frail older people in the development of a health service offered in municipal senior centers, aiming to improve frail older peoples’ possibilities of accessing the social communities of senior center and thereby improve their health and well-being.
Methods
The involvement was carried out as continuous panel meetings throughout the development process with a panel consisting of five senior center users, recruited through a senior center staff member functioning as gatekeeper. One researcher facilitated the panel meetings.
Results
The involvement brought forth important knowledge about the need of frail older people, when wanting to become part of a social community. Nevertheless, two main challenges emerged during the involvement period: 1) Recruiting frail older people proved difficult albeit a gatekeeper being used and 2) Facilitation of, and the methods used for, the panel meetings should be appropriate for involvement of the specific target group, in this case frail older people, to allow for all participants to be heard.
Conclusions
Considerations about the involvement concepts, methods and facilitation are crucial in order for challenges linked to involvement to be minimized, making it possible for the needs of frail older people to be heard and met in the development or improvement of community health services.
Abstract
Background
Public involvement is widely considered a way to improve health and quality of health services. The research literature reveals ambiguities concerning the added value and the ...unintended negative consequences of public involvement processes. The aim of this study was to identify, synthesize and present an overview of added value and unintended negative consequences of public involvement processes in the planning, development, and implementation of community health services.
Methods
36 peer-reviewed articles retrieved from a systematic search (published in a review article) in the CINAHL, Cochrane Library, Embase, PsycINFO, PubMed, ProQuest, and Scopus databases in 2021 were coded and extracted according to the aim of the study. A thematic synthesis was conducted involving (1) line-by-line text coding, (2) developing descriptive themes and (3) generating analytical themes.
Results
Two main themes with corresponding subthemes were identified providing an overview of the added value of public involvement processes (theme 1) at individual, service, and political levels. Unintended negative consequences (theme 2) show how individual resources is required, and uncertainty about the effect of involvement on services and power differences among providers and the public revealed.
Conclusions
The added value of public involvement processes is primarily reported on an individual and service level and often accompanied by unintended negative consequences. Professional facilitators and recruitment of a wider group of participants representing vulnerable groups is important to promote equality in public involvement.
Patients with STEMI were assigned to primary PCI with or without thrombectomy. At 180 days, there was no significant between-group difference in the primary outcome of death or cardiovascular events. ...Patients in the thrombectomy group had a higher rate of stroke at 30 days.
Primary percutaneous coronary intervention (PCI), when available, is the most effective method of achieving reperfusion in patients with ST-segment elevation myocardial infarction (STEMI).
1
However, a major limitation of primary PCI is the possibility of distal embolization of thrombus and failure to restore flow at the microvascular level. Measures of microvascular tissue reperfusion, such as the degree of ST-segment resolution or angiographic myocardial blush grade, have been shown to predict the rate of death after primary PCI.
2
,
3
Removal of the thrombus by manual thrombectomy before stent deployment has the potential of reducing distal embolization and improving microvascular perfusion. Small, randomized . . .
Abstract
Background
Mental illness can have negative impact on pregnant women, their infants and their families, including adverse birth outcomes, as well as place children at risk of developing ...mental illness later in life. It is recommended to offer additional support in the ante - and postnatal period, but to be able to offer appropriate, timely and effective care, more knowledge is needed on women's own experiences. The aim of this paper is to explore women's experiences with mental illness in the context of pregnancy and early motherhood, and how they experience and engage with supportive services.
Methods
This paper presents selected findings from an ethnographic field study carried out in a Danish municipality. The findings are based on data from 22 women, who were recruited when they were pregnant or had a newborn baby. The women were currently facing or had previously suffered from one or multiple mental health conditions.
Results
Analysis found that women with current or prior mental illness experienced a high level of fear, worries and uncertainty during pregnancy and early motherhood, which shaped how they engaged with supportive maternity services. Some were deeply worried about their mental health and reached out for support to cope with this. Concerns about being a bad mother and about the potential influence of their mental illness on their infants were common. Furthermore, some women were scared of being judged as unfit mothers and losing custody of their children. Many experienced stigma surrounding mental illness, making some more hesitant about reaching out for support.
Conclusions
By providing new insight into women's own perspectives, this study contributes with in-depth knowledge on women's experiences with mental illness during pregnancy and early motherhood, and illustrates how engaging with supportive services may be an ambivalent experience.
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